You can use it to buy altcoins!
Actually, there are lot of uses of bitcoin like you can used it to buy some altcoin or participate in some altcoin projects. Furthermore, I prefer fo used as investment where I could gain high income. Lastly, sometimes I used it to buy some stuffs that I need and want.
Agreed, it has got multiple usage. Same gives user the hope of earning which is not possible any of the other investment schemes. Whether it can be of long term or short term. This is the one that makes it the best and usage into trading and for investment purpose is the most common use of bitcoin.