I read my drafts aloud to my partner. This is a wonderful practice. I can’t say enough good things about it (or my partner.)
First, reading aloud slows ne down. I find grammar and usage errors. Redundancies become evident. Clumsy things that seemed like a good idea when I wrote them, run-on sentences, fragments. All of it can be seen during a read-through.
(I almost think I should use speech-to-text and read the first draft to create a second draft from it.)
Second, my partner is critical of the obvious gaps and problems. A question during read-aloud indicates a need for a rewrite to put the explanation in place.
Also, fiction is a mix of the expected and the unexpected. The “willing suspension of disbelief” idea means the writer is walking a fine line. Elements have to be believable in order to make the fantastic elements work. People are people, and many characters must have typical responses to typical situations.
Some characters will have responses to situations which are fantastic — heroic, or despicably evil, or outside the laws of physics because they’re a powerful mage — and these are what makes SFF so much fun to read (and write.)
I know it works when I get the “what?” during reading. One per chapter is about the limit, I think. Much more than that and we risk running off the rails or jumping a shark. Much less than that and we aren’t putting any fantasy into our SFF.