As far as I can tell, nobody blocks it. Google sometimes rejects emails where the from address doesn't match the real sending address, which is fair.
I guess the first couple of years were rocky, I hadn't figured out DKIM and SPF and all the other blood rituals yet. Back then I got blocked by Steam and banks. But ever since I set up the correct security it's been fine. Been my primary email for a long long time. All my online accounts are tied to it.
Incidentally, I also have free and unlimited aliases. But I don't usually bother because I have a rule to route all messages to unknown addresses into a special folder. I can give out any random address at my domain and it will always make it back to me. So much more convenient than logging into the website to generate an alias.