There is no standing rule of what crypto currency to follow. Like the dollar, every currency on earth will accept the bill anywhere in the world. One time I went to a country like their money doesn't count at all but when I offered a dollar it was very worthy in every shop and exchanges. Now what I see here is most probably being linked to bitcoin since it is the first of the digital coin created then thousands alternative coins followed to be created for each and every purpose. Like rules or requirements were set out to be able to make a new form of cryptocurrency coin, a group or an institution would like to create one basing on their respective specs and motive. They can make and open it to the public to share then do some trading for a project that is for a long term. Many currencies formed because of its purpose, features, stocks, records, how the platform works to benefit, the roadmap, whitepaper, airdrops for everyone and a lot more to change people's lives.