I think 2 factor authentication is just another way to wrench privacy from users. If it's an option, fine, but I should have the ability to forget my password and be locked out of my account forever if I want to.
That's exactly how I've been using Hexbear since its conception. This account is a couple months old and when there's an update I'll be locked out forever, just as I've done 5-6 times before.
in a lot of cases it is but there is serious use for 2FA and you can tell when it is because they will insist on using token generators/yubi keys that are much more secure and don't impact your privacy.
Use one of the services that temporarily provision the number for you for crypto. I used grizzly and it worked after some trying, but their account system is shit so make sure your account is fully created before you load up crypto.