Interviews are not required.
My guess is that half the things in your D’s application are not required- AP Chem? Advanced whatever? Not required. But all good to have, all things being equal. A strong application puts your best foot forward. And responding to emails from admissions- even from colleges which you consider to be rock bottom safeties “a dolphin could get admitted to this school”-- that’s called putting your best foot forward.
The point is that if the college is making an interview available, your D should be prepared to be moderately cooperative in making it happen.
Skip a dialysis appointment? No. Be late for a music rehearsal- after letting the director/conductor know that she has a college interview so will be half an hour late? Yes. That’s moderately cooperative. Stay up until 3 am the night before a big performance so she can squeeze in an interview in the early evening? No. Get an excused absence for gym class so she can interview? yes.
Not seeing how busy a HS kid might be compared to the person actually doing the interview. Who is likely squeezing your D into a full time job plus every other obligation this person might have.