Creature flips are both the most broadly accessible, and restrictive in terms of deckbuilding, of this general gameplan while there are an absolute plethora of great options, and you nearly always have access to something available for Polymorph targeting, cutting down on creatures is a tough call, and oftentimes you'll need to truly lean into some other gameplan, as is the case with Urza in artifact-based stax, or spellslinging control
Those don't have to be the same three permanents each time
Sure, nothing is stopping the powerful cards you bounced from being replayed, but everyone will have the chance to take them as they come rather than being crushed by the might of the player with the strongest board position
The card has a ton of homes, in other words, and its not just an extender for combos as it is in constructed formats
Against aggro, a Rhox War Monk is really hard to beat
Edgar Markov decks are flexible because of its Eminence ability, so protecting the Vampire Knight isn't necessarily as vital as with other Commander strategies