People must use bitcoin because it is the future money to all nations. If people would only know how good it is to have a bitcoin in their lives. Because the usage was very convenient and easy to use and the features also is very unique too.
Actually there is no necessity to use bitcoin. But if you want to make them think that bitcoin is important to use. You have to say that bitcoin can benefit you
Necessity is there, because it is a speculative currency which requires circulation moving in and out of wallets. This can be a transaction a trading, an gambling requirement anything. This helps in the growth of price with correspondence to the speculative approach made by the users.