From what I can tell, not much. They use dashes "-" instead of pluses "+".

But neither of these two options provide you with much privacy. Plus addresses, as others have pointed out, can be automatically stripped (just delete everything after the plus sign) and you get the real email behind it.

This service specifically I dont know the details, but it seems there is a unique prefix per user, but no "real email". So for instance if you use gmail you can have "sunnie@gmail.com" as your real email. You then use "sunnie+lemmy@gmail.com" for your lemmy account. If that email gets leaked out somehow, people can easily tell your real email address is "sunnie@gmail.com"

This service seems to do something very similar with the difference there is no base email, so there isnt a "sunnie@port87.com", there will only be "sunny-lemmy@port87.com". It is worth pointing out you might still be tracked because all your emails will be prefixed with "sunny". So although spammers wont be able to figure out your real email address they can just try something like "something-reddit@port87.com", and if multiple of your addresses leak it will be easy to link them all up to the same person.

This also creates A LOT of lock in. Because if the service shuts down you now have dozens of services for which you don't have means to access the emails anymore.