Is all this legal?

In my previous post I talked about being new to the industry and how I plan to get involved. I've done lots of research and can't wait to get in on the cryptocurrency revolution!

My concern is legality. I've watched people make hundreds of thousands on Mining, lending and trading cryptocurrency my question is if there is any legal risk?

Let's say you make a lot of money and you then exchange that crypto for "dollars" do you have to pay tax or is there fear of laundering? Could you get questions at the bank of why you are randomly depositing large sums of money?

Pardon if my question is dumb, I realize the reason crypto was brought up was to avoid government central banking or third party interference. I am just curious on if there is any risk here!

Thanks in advance!