> In short, stable matches mean nothing when nobody is committed and the best options might exist outside of the matchmaking pool

This is wrong. Stable matches still mean something, and in fact probably mean quite a lot.

You are given a much better match than a random pairing. If you still aren't interested, you can decline. If you go on a date and it doesn't work out, you can decline.

Nothing forces you to use this process, it is just an offer of a significantly better than random matching to what you might prefer.

It doesn't even need to account for preferences not covered by the questionnaire.