Our Government here will always question people who become rich instantly, sometimes they will relate all the wealth to drugs and smuggling so they can send us to jail for a questionable wealth and not paying taxes. they will do background checking, even if they dont find any illegal activities we did they still think that we do illegal. What if I become rich because of BTC do you think they will believe if I say that its bitcoin that making me rich? How will I explained to them?
If you live in a country where you are already paying taxes on your crypto earnings, then you should be fine. If you don't, then just make sure you keep a record of the transactions you have made so that you can provide proof that your earnings were legal, should you ever need to prove it (of course this is assuming all your BTC / crypto transactions were legal).