Depends on the situation, I know it would have been useful for my farming party to just go around teleporting in the second floor to get faster to the take point in the far east and not having to deal with the deer near the fist one. But they would level up much slower (or nothing at all).
Well, okay, you can do that too. I was more just commenting on you cannot use it to escape bad situations unless it's on a Floor you've already explored. New floors have it locked entirely.
Honestly, there's enough EXP as is, especially with how easy FoEs are again.
Well for example, on the Floor 3 with the Stalkers, there are chests and quests to get to certain areas. You can use an Ariadne Thread to just rush it with no exit strategy but that's also 100en or you can just Floor Jump out for free.
Still can't do that until you've explored the floor :x But, yeah, I used Floor Jump to deal with that triple Stalker room.