A useful ability we might want in the future is to safely cast a RawSpan to a Span<T> if T is a fully-inhabited type (with the correct alignment). That would be impossible if each individual load from a RawSpan performed a "freeze" operation.
(Apologies for the three replies in a row; I thought it would be more courteous to create a new reply for a substantially different point than to edit it into an existing reply and have it potentially be missed by those interested in this thread.)