There was a period of time where people were fighting each other to get colorful pieces of cardboard with Japanese monsters on them
Less than free, in fact, as you get 2 mana to use on them
Remembering when to play cards, the art of attacking and defending, and when to pull spell cards seemed a lot more difficult than other TCGs Ive played
Being able to just use one or two mana per opponent's turn on instants while drawing 2+ cards seems extremely powerful
Given that Atraxa herself, the Phyrexian angel horror and one of the most popular commanders, is also arguably one of the most popular cards that uses the proliferate ability, its no surprise that Atraxas Skitterfang is primed for combos using the ability
The more opponents you have the easier it is to activate the flip condition