That’s the entire point of Unreal Studio subscription. You’d pay like 20 (or more) dollars monthly per user. No royalty costs because it’s impossible to say what is the Unreal-generated “income” here.
Unreal Studio is free for charge for a limited time (beta phase), so non-gaming industries couldn’t resist from using Unreal.
Just check what’s displayed at the Unreal Studio overview page: “100% royalty-free license”