The daily dungeon buy-in cost is relatively unreasonably expensive as it is the same cost as the 3-day event dungeon.
The costs for both dungeons is the same.
The incentives for for 3-day event dungeon is three times larger plus a potential leaderboard reward.
There really doesn’t seem to be much value in buying the extra tokens for the daily dungeon. It would give you another couple of attacks to achieve the top chest if you messed up your original 2 attacks (which are enough to earn all 3 prizes with clean runs). But without the additional leaderboard finishing position bonuses there are no extra medals to be won to progress to higher tiers faster.