Yes, absolutely! I don't see a future where one coin rule all the others. Maybe iota will be the dominant for the IOT market. Some other will be used for amazon, other for alibaba. I think there will be multiple coins being used at the same time. So exchanges will be used a lot.

There's no such a thing as garanteed return in the crypto world. Maybe in traditional financial market you get almost garanteed profit, but only 2 to 5% a year.

You might want to day trade with alcoins, margin trade, lend in an exchange for some profit or just hold. All has it's risks and rewards.

I dont know if bitcoin is going to be useful to banks, almost sure it wont. Now blockchain, that technology that powers bitcoin, i'm sure it will. Not only banks but multiple sector across all types of industries.