Not any easier than to do the exact same thing with cash, and in fact, far more difficult since there remains a permanent and immutable record of the fact you have done this. Centralized exchanges and payment processors would very quickly report you even if you tried to do this.
Well yeah, if the only way to own bitcoin was through centralized exchanges and there was no such thing as self-custody then sure. but people dont have to keep their bitcoin on centralized exchanges and they don't need payment processors for paying someone using bitcoin. they only need those things as endpoints, aka, cashing out. but even cashing out can be done without them as I'm sure you already know.
I actually think the limit should be higher, maybe in the region of $1,000, especially over time as bitcoin continues to gain value against the rapid inflation of the dollar. But better to get a low limit passed first and then work on increasing it.
the limit should be unlimited. if someone has already pay taxes on money they put into bitcoin, why should they have to pay taxes on it again? eventually the government wins and gets everything.