Sunk cost fallacy could be a sign that you don't trust your present judgement compared to when you made the original decision to put the resources in

Definitely useful. I personally find the two have a very different emotional/internal "flavor" - I can tell when I want to avoid a sunk cost vs when I'm in a bad mood and just don't want to deal with a cost - but that's not necessarily always true of me, much less anyone else.