For me, an emulator solves the 80% case: I'm soliciting quick feedback on specific changes. I'd happily use one as TestFlight for dev builds. I'm optimistic my users (my team) would find it more convenient, less interruptive. I'll ask them.
The other 20% is stuff that doesn't work in an emulator. Usually Apple, certificates.
It's enough of a minefield that QA means real devices, unfortunately. Used phones are vastly cheaper than "false alarm" bug reports.
> in our experience, nobody wants to push to those platform that frequently, and force many upgrades of the app every day, so instead they do nightly builds at best
If my team's big enough for daily builds, we have continuous deployment (Fastlane or similar). Strictly speaking, the pain is the build step (slow; can be flaky), not pushing the artifact.
I hope this is helpful. Feel free to dig deeper, I'll keep an eye on this thread.