Bitcoins are a kind of currency used in (on the Internet) internet. It was created in nineteen eighty, (comma needed with the conjunction to join to complete sentences together. Only a comma or a conjunction is not sufficient to join two independent clauses together. You need them both to do so) but it is (has been; we need the present perfect with words such as since and for when you are referring to a moment which started in the past and continues up to now. What you have done is the literal translation from Spanish to English, where you can use the present simple with desde and durante) used around the world since two thousand eight. It is not very common, (a good use of the comma to join two independent clauses here. Well done) but it is getting more and more famous among people who buy in the net (on the net; it is always on the net, not in).
Bitcoins are the only currency in the world that don’t (doesn´t, subject verb agreement) need a Central Bank or a government behind it. The costumers only need a free software, that they can download from internet (the internet), for operating (no need for the comma, and the purpose of people is with the infinitive of purpose, not for + ing, this explains the use of objects. In this case, it is people doing the downloading to do something) with the bitcoins.
Some people say that bitcoins are not money because real money need (real money needs) a (no need for an article with an abstract an abstract noun.) physical support. The most common physical support is the gold (the definite article is unnecessary because we are talking about gold in general, not a particular kind of gold). All Central Banks (All the Central banks, because we have already spoken about central banks before. The second time you refer to a noun in a piece of text the noun takes the definite article.) in the world have the same amount in gold than (it is same as, not same than) in currency. That is the reason because currency don’t (doesn´t) have the same value. Virtual bitcoins have not (have no gold or don´t have any gold) gold for supporting themselves. Its value depends on maths because the creators can make (print money, not make money in this case) the quantity of currency that they want.
The (the definite article is not needed here, as Last sufficiently determines the noun.) last year has been incredible (incredible, because adverbs modify adjectives, verbs and other adverbs.) bad for countries and its (their) economy. All the financial products and stock markets got (went down) down and lost money. Bitcoins grow up (went up, the verb expressing movement in economy is go up and dow, or grow. Grow up is used for people, in the sense that the person is maturing, aging at growing.) in spite of that. People who bought bitcoins won (made, not won. Winning refers to competitions.) a profit of 4800%!. It was amazing, (comma needed. Two independent clauses) and the bitcoin´s creators said that it was a dangerous product to win (earn can also be used but not win.) money. Nevertheles, (a comma is always needed after words like nevertheless, however, so, therefore, although.) people still want to win (earn or make, not win) money with the bitcoins.
The use of bitcoins demonstrate (demonstrates) that people is (are) starting to buy and sell things without banks. The banks have important functions nowadays, (a comma to join two independent clauses together.) but it´s seems that they only want to win (earn or make) more and more money, (comma before or after conjunctive adverbs) although people is (are) getting poorer. On the other hand, (a comma after these transitional verbs or phrases) virtual selling are getting higher and people don’t need real currencies as they need (needed because we are talking about before; as in the past) before. People don’t want to pay commissions when they change currencies, for instance when they travel abroad. For all these kind of reasons (adverbial phrases need a comma after them if they are used at the start of the sentence. They don´t need it if they are placed at the end of the sentence) they usually trust in others kind of payment (other with plurals and another with singulars), like the bitcoins.
Will bitcoins be the future (mode of payment) payment? It is difficult to prognosticate it, (comma needed to join two independent clauses) but we can talk about few tendencies. The most important tendency is that people don’t use currency even (even if means aunque, even means incluso. If you use even, you need to use even when they have it) they have it when they pay something (pay for something). Since I have credit card (a credit card. It is a singular noun and it needs to be determined, and we need a comma after this adverbial) I prefer to pay with it in the supermarkets, restaurants and cinemas. I don’t like to pay with credit card when I go to the bars with my friends because you can spend a lot of money. Because I usually pay with credit card, (comma after the adverbial if it is at the beginning of the sentence) the bank earn (earns, the third person singular with a singular noun.) money with my shops (shopping is the word, but you could use from my spending) and I don’t know why, I pay every year for having credit card anyway (to have a credit card. Purpose of a person´s action is with the infinitive, not for + ing and credit card is a singular noun, which needs to be determined). Maybe in a few years, (a comma after an adverbial at the beginning of the sentence) we will be able to pay in virtual bars with bitcoins!