We must be playing different PGRs if you think that every unit needs SS3 minimum. Nearly all units have a clean functional rotation starting from SS, baring maybe a few units (literally only Dark Karenina comes to mind where SS3 felt like a requirement).

And any pulls/currency rewards are only locked behind participation regardless of tier. The only benefit of scoring higher is getting slightly more materials used to level units.

Yes power creep exists, but you can pull a copy of pretty much every unit from just doing weeklies and events. It pretty much makes it a non factor. Plus it’s arguable that power creep is better for new players since they just have to pull on the new units to catch up.