That’s pretty much exactly it. Not much benefit for only one application. But I have multiple apps that all recieves notifications via UnifiedPush. My UnifiedPush client (ntfy) stays running in the background, the rest of the apps can go to sleep and get woken up if something haopens.
Signal uses Play Services for its push notifications. It does have a fallback method which maintains a connection to their servers to get message notifications. It requires changing some battery optimisation settings which might have some minor battery impacts.
Personally I’m using Molly which implements UnifiedPush for Push Notifications without Molly/Signal needing to run in the background constantly. Also swaps a few other Google dependencies (like location pins) with open source alternatives.
Having the second profile with Google Services is a good idea though. That was what I used to do before I shed my last few Google dependencies.
I’m using Bank Australia with GrapheneOS and it works well. Does the Comm Banks builtin tap and pay work on GrapheneOS at all? Assuming they still have their own version, I haven’t been with them in a while.