Four mana is still a relatively important downside to take into account, though
Landfall Whenever a land you control enters, if its your main phase, theres an additional combat phase after this phase
In a casual format like Commander where people like to play with big, splashy cards and fun creatures, an enchantment like Humility can completely turn the game on its head with a powerful effect that nerfs most commanders and popular creature cards into oblivion
This is better than Ill-Gotten Gains and Past in Flames combined
In my years of personal experience, examining good decklists, and talking to people much smarter than me, 50 mana sources is about the right number for most decks to shoot for, usually 37 lands and 13 ramp sources for a general budget deck
Weve heard far too many stories here at Card Gamer of people losing, disposing of or damaging cards that can sometimes be sold for much higher values than they were purchased for, so wed highly recommend keeping an eye on the cards your child has and making sure that the most valuable (or the ones that have the most potential value, usually determined by their rarity) are taken care of