The only benefits I can see of "Apps", are the developer get's access to private information they really don't need.
Yeah, they get to be on the "App Store". But the "App Store" is a totally unnecessary concept introduced by Apple/Google so they could scrape a huge percentage in sales.
Web browsers have good (not perfect) sandboxing, costs no fees to "submit" and are accessible to everyone on every phone.
In many other cases I agree with you.
Even if it's gRPC or something more exotic, it'll be over TLS (you best hope it is).
You can have a webapp cached locally on your device. PWAs allow developers to create an SPA you can open from your homescreen, and to do that API interaction the same way as a native app.
I hope you and your family are well, and it's great that tech helped. But please, don't think that because this tech worked in this instance it can't be made safer and securer.