I can see the argument against, though: you could just sync yourself to just the right level to keep getting exp in a specific area and level up there all the way to 99 without having to ever change camps.

But, I mean, let's be real here, the experience grind is not a challenge any more, instead of spending weeks in the level range for, say, a Yuhtunga Jungle exp party, now you can rush past that range in a few hours anyway, so whatever. It doesn't seem like experience points are supposed to be a challenge any more, so why use "then exp won't be a challenge" to justify design decisions.