It is safe, I recall a time when the bank questioned the source of my funds. I disclosed that it was from my earnings in cryptocurrency. I provided them with any necessary information and proof they requested. After reviewing the information, they did not ask any further questions, even regarding my cryptocurrency funds.
Depends what country you're from, in my country there's a lot of taxes and lots of bureaucratic paperwork that you have to deal with and the time that you'll waste on that thing would be better off somewhere more worthwhile, they don't enforce the crypto taxation in the country so much so I don't think that it's necessary to tell the bank that you're dealing with crypto, you can probably just go with the cold hard cash kind instead of bank transfers and in my opinion, I don't think that it's a really good idea to be giving that money(tax) that literally protests about the exploitation and the obsoleted system of the banks so as much as I can do, I have to make sure that I'm reaping all the benefits, almost all the stuff in my country's got a tax already so I don't think that they wouldn't mind me not paying since I'm buying other stuff anyway.
I guess that's how it is. Certain countries have very strict regulations when it comes to cryptocurrency. In such situations, it's advisable to avoid disclosing any information, even to banks, to prevent any paperwork and the potential freezing of funds if you cannot provide the required details.