And what's the solution when your domain will be added to some blacklist and won't be allowed to be used when registering on a website? I see it happening with older email privacy services.

most services like this one let you use your own custom domain -- i'm working on something similar just now. there's a privacy tradeoff there, but you won't be blocked by websites.

How is it different from simplelogin or anonaddy?

author here —- the short answer is that this also blocks tracking pixels! i’d also say that both simplelogin and anonaddy have a lot of features and can be a bit complex, whereas i’m really focusing on simplicity & UX.