Because of soaring value of
BTC, scammers are also soaring active promoting their tactics to get more victims, as I have a website which is crypto related and the email was public seen before, in return I receive these kind of emails almost everyday, well of course, it's going to spam folder in anyways.
So I suggest to become more aware of this scams. Even twitter has massive spam of tweets from scammers.
Are you sure of this, and you're not signed up to any other accounts with this email that is crypto related? I checked my email registered with Bitmain and haven't received anything.
I have an account on them but never receive any email related to them. Most probably, the email used by OP is somewhat used on any other crypto related website.