it's because class determines how much capacity they have. think of it like a bucket. a B-class guide can only take so much water from an esper. an F-class would be akin to a cup i think, meanwhile an S-class guide would be a pool.
and matching rate is just about how efficient it is, think water pressure. if it's just a low trickle, it'd take too long no matter how vast your capacity.
and in the case of this stpry, i think what matters more is the fact that the MC's guiding wasn't painful to the ML. so it wouldn't matter if someone with a higher sync/match rate showed up, if it was still painful
This Guideverse theory of Class and Rate is somewhat stupid. Like Whats the point of identifying them based on Classes when Matching rate is what matters the most. I see a lot of Stories with s class who has B-F guides with a matching rate of 70+%. Come on
So is Esper S and S Class Guide but with 20% matching rate is useless?