Foolish Burial Grounds is a useful way of sending cards like Virtual World Gate - Qinglong to the graveyard, whose effect allows it to be banished in order to add a Virtual World Monster from your deck to your hand
If your opponent Special Summons a Ritual, Fusion, Synchro, Xyz, and/or Link Monster(s) (except during the Damage Step): You can Tribute 1 other LIGHT or DARK monster, then target 1 of those Special Summoned monsters
The commander deck composition flexes with your strategy - the categories stay, the counts shift
That's a legitimate mistake that a lot of new players make when they play Yu-Gi-Oh!, and it's called missing the activation timing
While you control this Fusion Summoned card, your opponent cannot target other monsters you control with monster effects
its worth paying more mana overall if you can save mana on a key turn later on