Doesn’t seem like a bonus. Your custom domain could just be blocked wholesale. Hide my email uses iCloud, not a separate domain. iCloud addresses probably won’t be blocked as that’s the default email given for hundred million plus Apple accounts.
Fastmail by default uses @fastmail.com addresses for masked email, same as their cheapest plan, so when I used it there was never anything blocked except the occasional site that only accepts gmail addresses (yep, they exist). Personally I prefer it that way for personal use, the custom domain sacrifices anonymity, but it might be nice for business users.
Fastmail is still like 0.1% of users. If you're a "growth & engagement" company you're probably better off banning that domain wholesale and as a bonus will get rid of tech-savvy ad/tracker blocker users without making any impact to your target market.
The advantage of iCloud is that it's a domain laymen use - those same laymen the "growth & engagement" scum wants to track and spam. They can't just ban it wholesale without alienating a large chunk of their target market (and a pretty lucrative one at that, since Apple hardware is expensive).
A while ago I ran into the first site that told me I couldn't use my fastmail masked email: remove.bg.
I don't know if they block every fastmail.com address, or if they somehow check if it's a masked email.
Lots of random weirdness for me trying to use mine. Most recent example was trying to checkout as a guest on Little Caesar’s app. Kept declining my Apple Pay transaction without telling me why — changed the email and it worked.
There’s only been a handful of times I’ve used it, maybe 12? At least a few of those times it wouldn’t even let me submit it saying it was an “invalid email”. Couldn’t even get past the validation.
Any idea if using a custom domain would have worked better here? I wouldn't be surprised if some places only accept email addresses from a small set of "known" providers
Companies blocking disposable email domains are doing it to prevent many users from using their service with a disposable email.
A custom domain that only I use specifically for disposable emails would look indistinguishable from any other custom domain out there, and nobody else would have used it for them to even be aware of its existence.
To block it pre-emptively, they’d have to either be omniscient or block every single custom domain in existence. The former I highly doubt is the case, the latter would generally do more harm than good to them.
