She does have to attack to do her thing, but the fact she can remove lore counters from multiple Sagas at once is particularly potent, as it can allow you to repeat triggers on your Sagas, and if they happen to be Saga Creatures, she makes sure they stay on the battlefield to attack and block longer
For example, if two creatures you control with lifelink deal combat damage at the same time, Excalibur II's ability will trigger twice
Without these the Onion Knight is pretty much a Joke Character
Eventually, opponents will struggle to keep up, especially since Emerald Steel has the draw engine to create a bigger resource gap
Well, the two that see the most play are Bucky - Squirrel Squeak Tutor and Blue Fairy - Rewarding Good Deeds and they share some rather obvious traits: Cost: They are cheap, and can be easily played WITH a Floodborn shifted character as early as turn four in some cases
While resolving Kefka, Court Mage's last ability, the next opponent in turn order chooses a permanent they control, then each other opponent in turn order does the same