PotD (and HoH) spamming is recommended for leveling alt jobs—especially DPS, as the queues are usually shorter for them as opposed to leveling dungeons. Tanks and healers are usually recommended to do leveling dungeons because they get fast queues, and you get a sizable chunk of EXP from doing a leveling dungeon you’re in level-range of.

For levels 1-60, it’s recommended to spam PotD 51-60. For levels 61-70, HoH 21-30. Personally, I recommend also trying to mix in daily roulettes and perhaps a few leveling dungeons, as I don’t think that PotD/HoH gives you a decent opportunity to really practice your rotation since the mobs die super fast—it really only leaves you with boss fights to practice single-target on. But it’s entirely up to the individual what they do. I go for the mixture for more practice and to break up the monotony, because it can be really boring to spam the same 10 floors over and over again.