Reading through this thread has me thinking now. I just made a signer for Linux. And I've made an app that logs in with the signer. But it would be smoother if the main app had a signer. But what if you didn't want to run say your social client ... Every app other than it would depend on it running. I single signer app in the background is way less resource intensive.

I guess you could add it in settings and turn it on only if you want to roll that way. Otherwise run a lone signer.

Other thing is Android, iOS , windows, Linux all talk differently, so every cross platform app would have to know how to talk to all of them... Which means we need standards.