This is a logical approach when many of the launches are delivering your own payloads to orbit. Best case, no issues and you get more data and more launches out of a booster. Worst case, you loose a few dozen Starlinks and you learn a lot about how your vehicle will eventually fail and maybe learn where to design in improvements to avoid that specific failure case.

That said, I'm sure they are still well within the safety margins, but pushing a bit (with little risk) to be able to see if your margins are correctly placed is just smart.