They all give you access to more, and hopefully better resources
Exiling and putting a cage counter on Hateflayer and Tree of Perdition allows you to take out one opponent per turn as long as you have the mana
P/T Set Number 158 Language Franais Legal Formats Commander, Legacy, Vintage Not Legal Formats Alchemy, Brawl, Competitive Brawl, Historic, Modern, Pauper, Pioneer, Standard, Timeless Rulings (6/6/2025) The ninjutsu ability can be activated only after blockers have been declared
Costing seven mana is quite a cost, so by only playing one copy you're not as likely to draw this in your opening hand
In cube life totals are more generally relevant (as in most matchups do make two life a cost, even if small) while in constructed there are far more matchups where it simply doesn't matter at all
This discounting mechanic scales rapidly, allowing big-impact plays much earlier than opponents expect, and it pairs well with self-mill strategies that keep the graveyard stocked