Editing is mainly used to catch issues of spelling, grammar, punctuation, word use, etc.

Beta readers aren’t looking for those types of things.  Instead, they’re paying more attention to the overall story, characters, and with the Hidden Gems Beta Reader program, they’re specifically answering the questions that the author has asked in their questionnaire – which can be about a wide variety of things to do with the book (or even the blurb or cover).

Editing requires special skills and beta readers are not expected to be able to provide editing feedback unless specifically asked as one of the questions (although if it is, it should be more of a general question about whether they noticed any sorts of editing issues, not to specifically list out the issues they found).