You probably pay more if using a gamepass, but you also try a lot more games.
If you played as many games without a gamepass as with one, you’d pay a lot more.
But without a gamepass, you usually restrict yourself to fewer games.
Whether removing such restriction is worth the (not as significant) additional cost is subjective.
So there’s an actual case for subscription in cases like this.
(The reason subscriptions make some sense here is because digital items are artificially limited. With physical items or services subscriptions are almost always a money grab. But with artificially limited things, such as digital items, subscriptions can definitely be reasonable.)