An intermediate UI abstraction may hold some appeal if you maintain apps delivering equivalent function across a diversity of device types and capabilities.

The best example I can think of would be a streaming media service that ships an app for hundreds of different TVs, STBs, dongles, NASes, mobile devices etc etc that all front basically the same service.

> shipping the whole app as a single s-exp

Be careful what you wish for. You may reinvent Lotus Notes by mistake.