The best use case is for top of funnel communities, let me explain:
It is important because it lowers the barrier to entry: new folk don't have to fish out their credit cards, they can just hit join, fill some questions out and get in on the community. (reduces friction)
But here's the main benefit: when that trial period ends, the freebie seekers and spammy accounts immediately get pulled out.
Basically, they can only stay for as long as the trial period is. Pretty cool, and (hopefully) not technically difficult for the Skool team to implement.
Would you use this feature?