Is there a point to boss rush?
I've currently cleared all the dungeons in my reach and the only place left for current "exploration" is the Boss Rush for Jade Way... well, the first three bosses anyway.
However, the first two of three bosses don't seem to drop any loot, and this is otherwise rather poor as experience farming goes.
Is the only point of boss rush setting a time for the bragging rights, or does mad loot reside at the end making it a worthwile way to spend a day?
Solution 1:
Boss rush lets you fight bosses a lot faster than it would if you were to trek the dungeon. This has two general purposes, plus one thing that happens in the post-game.
If the first boss has a very nice drop (like Samhain), then it's a lot faster to just boss rush to try for it and confirm success/failure than to beat through the first 5 floors. If you fail, then you don't stand to lose much if you reload.
If there are enough bosses with really nice drops, then doing boss rush will let you fight them without the wear of the dungeon levels to fight them all in sequence or the burden of not having room for treasure drops from trekking 50 floors.
It all boils down to "Not spending so much time trekking in dungeons when what you want is held by the boss". All bosses have drops, but they're not guaranteed drops.
In the post-game...
The Crystal Nightmare dungeon's boss rush has unique drops that are only available in the boss rush mode. These comprise primarily of the second-most-powerful pieces of each kind of equipment. So, it's actually a pretty good idea to do this. If you're high enough level, at any rate.