"Qualifying customers may be eligible for credits toward the Unity Runtime Fee based on the adoption of Unity services beyond the Editor, such as Unity Gaming Services or Unity LevelPlay mediation for mobile ad-supported games. "
Either way they appear to be trying corral devs into using their advertising software. LevelPlay is IronSouce.
Combine this with their Gaming services. And they would control your backend. They would get a share of ad revenue directly, because it's their ad network.
At that point (this is just my opinion) you're just sort of their employee but without the benefits.
