In the late game in Commander, say you have ten mana available, you can cast this mid game and if it is not removed, you have seven mana to cast cards from your graveyard
You can even use that mana right away, providing a sort of rebate on its steep casting cost
Dionus, Elvish Archdruid Dionus, Elvish Archdruid warrants a mention considering how easy it is to tap elves, be it with cards like Heritage Druid or with something like Cryptolith Rite
The list is probably going to be long
Its somewhat slower than most formats, but it avoids over complexity that some have complained with in some comparable formats
This is useful because you know there will be a creature to use the equipment right away, and you can almost think of these equipment cards as creature spells when deck building