Can an accessory be “compatible” if it blocks normal controls?

Physical fit is only one part of accessory compatibility. If a case technically fits but blocks a charging port, interferes with a control, or makes normal maintenance impractical, calling it simply “compatible” can mislead readers.

I prefer to separate “fits” from “works without interfering with normal use.”

Strong agree. I have returned cases that fit perfectly and made the device worse to use.

That distinction also helps with parts: mechanical fit, electrical compatibility, and practical usability are different claims.

Exactly. A good compatibility note should say which kind of compatibility was actually checked.