realistically no one is going that far to invite crafters/uselessppl for an insignificant buff, it is a possible scenario but it is not gonna be something that everyone does like "abandoning leves".

Is it fostering good gameplay to reward players for adding useless members to their party?
what is good gameplay? it's subjective.

sure, it might be a bad design, but it is a bad design that people actually enjoys, removing it would cause nothing but setting these people to rage mode and ensues another angry thread.