Does Leafy give EP regen?

The catch is the element: Vitality Blooms only feeds Grass teammates standing inside its circle. Inside it they regain EP at about 2.4 per second and build ultimate energy at the same time, so the field speeds up both skills and ultimates. A non-Grass ally standing in the same spot gets nothing from it, and the field also heals only Grass teammates.

That makes Leafy, a Grass boss Aniimo, a support for Grass teams rather than a general energy battery. It is a top-priority teammate for Irisalis for exactly this reason, bringing Grass and EP support in one slot. If your team is mixed, Besauce is the option whose restoration is not tied to an element.

What regen does in Aniimo

Regen is a support role built around the team's energy pool. Restoring EP faster means skills come back sooner and cooldowns effectively shrink. Supports scale with different stats: some heal off HP, some scale regen effects with Regen, and some scale with Attack.

For Leafy specifically, Spirited Feather grants cooldown reduction once potential regeneration reaches 15 or higher, which lowers the cooldowns on Leafy's fields. Shorter field cooldowns mean more time with Vitality Blooms on the ground.

Not settled: The field's rate is about 2.4 EP per second, and how much larger it gets when Leafy is used as an assist is not given as a figure.