It's depend from country to country and theirs laws.
In mine, we have to pay taxs if we make profits with the price. (Let's say you buy at 700$ and sell at 800$). As long you don't sell your bitcoin then no taxs.
Some of us buy it with Paypal or others, to hide what we are doing with it so in case they control, they see the money is sent to paypal, not to an exchange platform.
I remember a period some banks were blocking banks transfers to Kraken telling us "risk fraud" LOL who asked your opinion
