Super quickly, sleeves make it easier to shuffle and hold your cards and stop you from damaging the edges of your cards when you do things like shuffling
They're fun for five minutes
cards increases, it will become easier to use your Leader effect and effects that rest your opponent's Characters at the same time
When you call the ritual, you can exchange two cards, when you call the fusion, you can revive a lower-class monster from your own GY, when you call the synchro, you can strengthen yourself, and when you call the X, you can weaken the whole opponent
While it's far from the most playable card, it's not a bad land necessarily
Especially if gaining life - inherently hostile - were part of the mix