Comment by rincebrain

It's possible to do both, you just need to be cognizant of what you're doing in both positions.

A tricky part becomes when you don't have both roles for something, like SRE-developed tools that are maintained by the ones writing them, and you need to strike the balance yourselves until/unless you wind up with that split. If you're not aware of both hats and juggling wearing them intentionally, in that case, you can wind up with tools out of SRE that are worse than any SWE-only tool might ever be, because the SREs sometimes think they won't make the same mistakes, but all the same feature-focused things apply for SRE-written tools too...