I recently viewed a presentation about this, https://assets.moodlemoot.org/sites/77/20180704162809/Day2_DRAFT_turning_moodle_pwa.pdf
You could technically do it, but it will be a LOT of work and apart from that:
- You won't be able to do the intensive caching the app does
- It won't work offline as the app does (for example, SCORM module downloads and unzip the package for offline)
- Push notifications will stop working (you will have to implement your own solution)
- Same for local notifications, you will have to create your own implementation
- Some functionalities will behave differently, like opening files directly with the native app
And I suppose there will be more issues...