I agree, when it comes to cryptocurrencies we act as our own bank, and we should take extra precautions when divulging information about our crypto investments, especially if you carry your assets around on your mobile phone, this increases the risk of getting robbed.
A thief is less likely to force you to make a transfer from your bank as this would give away their identity, but a Blockchain transaction can be mixed and the trace would be lost.

Even if one deletes their account on a website after submitting personal information, that information is not deleted. The best security is to keep your data private.