SpaceX used to pay AS33891 Core-Backbone GmbH to reach AS3320 now they pay 1299 (German (landed) Starlink users) for that

Interlink is to get to France Telecom/ Orange from German Starlink users

And to get Italian/Bulgarian landed traffic to AS3320

From what I see most of the traffic that flows via inter.link from SpaceX is point to point traffic. Not regular IP transit like what they get from 1299 or GTT

SpaceX is settlement free in Germany, customer elsewhere.