I think that one of the biggest winners with this card is Kinnan, Bonder Prodigy because it offers a line where you dont always need colored mana to make Kinnan work
You don't have to add four copies of each card to your deck though, and sometimes it's beneficial to have fewer copies and make room for other important cards
While this card has likely been power-crept out of any real play (due to the fact that any player with open mana can also create lots of their own furry, long-tailed creatures when the Liege bites it), it still stands as an important historical Squirrel-enabler, likely leading to it retaining a price above $5
You can certainly play a mono-color deck
It falls into the category of final tweaks where Im concerned
It's one thing to stop your opponent's game plan by efficiently reacting to their plays, it's another entirely to just stop them from being able to play the game in the first place