The “different email providers” thing is an interesting caveat, but how are you proposing to make use of that caveat in software? It’s not that it’s impossible on the face of it, but any software that wanted to make use of it would AFAICT have to have a painstakingly hand-crafted database of domain rules, so that you accept lots of gmail.com addresses but not lots of ciphergoth.org addresses.
“A pile”, sure, but not millions.
The “different email providers” thing is an interesting caveat, but how are you proposing to make use of that caveat in software? It’s not that it’s impossible on the face of it, but any software that wanted to make use of it would AFAICT have to have a painstakingly hand-crafted database of domain rules, so that you accept lots of gmail.com addresses but not lots of ciphergoth.org addresses.