This is just a personal opinion of the person who wrote this article. I don't really think Bitcoin can be considered as being part of top currencies in the world. Base on my personal observation, less than 1% of the entire world population know the existence of Bitcoin and out of these percentage, only a few considers it has a currency for exchange of goods and services. The 99% left do not have a single idea of what Bitcoin is and even think about using it for their transactions.
There are many cryptocurrency are now existing and one of the most well know is bitcoin. We should consider bitcoin as the top and also well know cryptocurrency because of the things happen after it released. Many people are helped and earned a lot of money because of what bitcoin had. It gives many people an opportunities to give a profit and get some income to use in our daily expenses. This is actually categorized on how market value had one cryptocurrency.