2how to actually use it
Place it, click it, mine it straight back up. The buff stays on you once the ball is in your pocket, so there is no reason to leave one standing in the world unless you like the look. Reapplying costs nothing, there is no cooldown, and in multiplayer everyone can take a turn on the same ball.
the habit worth building
The magic bonuses are modest individually but they are free and they hold for the whole session, so any mage should be clicking it before every boss without thinking about it. The thing people forget is that dying wipes it. Reapply after every death, not just at the start of the night.
the crafting side
It is also a crafting station, and the recipe list behind it is the better reason to own one. Endless ammo pouches, the waterfall and lavafall blocks builders want, water candles and several of the bottled jump accessories all route through it. If you build at all, it belongs in the crafting room rather than in your pocket.