Spammers often strip dot aliases in my experience. This doesn't seem like doing anything to solve that problem. I mean, if citigroup.joe gets dot-stripped, then citigroup@mailhero.io gets that spam instead of joe, but odds are joe will just end up getting somebody else's spam anyway, so it's not really much of a win unless you're careful to pick a username that won't be used as an alias, and then you have the problem of having to give out addresses like citigroup.rkcj92o8I@mailhero.io.

Not seeing the value prop over Mailinator.