Are SBTs any different than SSI ?

Hello guys !

I'm sorry if it makes no sense to you. But i've read quite a lot on SBTs and SSI. And i can't understand the difference. They both serve to prove identity, with : An Issuer (to issue the credential), an Holder, and a verifier.

In both example, it's the same usecase, with the diploma from university.

Am i the only one to not understand the difference ?