My main reason for investing in bitcoin is the high liquidity of Bitcoin and thus the ease with which I can trade it if I need money for something whilst holding it.
Another reason is the fact that it is very popular and also can sometimes be accepted by some merchants as payment for goods.
No one uses Bitcoin to pay for the goods because every bitcoin transaction takes a lot of time to verify. Most Bitcoin is no longer as anonymous and people are tending to use XMR for commercial purposes as it is unregulated or can use XRP to pay for because the technology of ripple is being made by many banks apply
It can be used if it's a P2P transaction similar to the barter model. Sure, it's not that practical, but it still functions quite well if someone is making larger payments once in a while, such as for services rendered.
It may not be perfectly anonymous, but it's not easily traceable either. If you did something illegal with it, I'm sure they would go through the effort to find you without hesitation. But if there's no active reason to target you, they can't exactly go around trying to dig up who is behind every transaction. There's way to much data to swim through. That's why some people can use it to send money for small-medium transactions abroad and avoid having to claim it.