The can't be blocked phrase on equipment is strong, and so is the easy way to bounce it back to hand
Its most common use is to copy a simple, cheap spell, like a 1-mana cantrip or a light removal spell
Again, I want to stress how slow these Pokemon are to use, so you'll not want to use more than one, and you'll definitely want to have a Switch trainer in your deck since both Aggron and Mega Aggron require four energy cards to retreat
Most players can't risk taking the damage and giving that player draw, so they chump block
Keeper of the Accord (Commander Legends) It can be easy to find yourself behind on boardstate in Commander
Some cards like Enter the Infinite and Finale of Revelation are pretty much designed to close out a match