Because the SPFL ask the clubs to try their best to reach an agreement first before they step in.
I actually remember reading about the rule a few years ago, if memory serves it was first brought in with the intention of it being used at the start of a season so teams can, if they wish, play in a glamour pre season tournament somewhere and earn more cash, not so they can go on a jolly in the Sun in winter.
I believe it can only be done once per season as well, but I can’t remember where I read that so I’m happy to stand corrected if this is not the case.