Idle shutdown/quit is still available, but the nice thing about the custom shutdown timer is that it can be used when live TV is being displayed and people want to fall asleep with the TV on, since video playing will prevent the idle timer from working. Being able to quit Kodi completely is also sometimes necessary for the box to sleep the display when on Android, IIRC.
Slightly related, but it would also be awesome to expand on the options for both the idle timer and the custom timer with things like:
- Stop playback
- Screen saver
- Log out profile and show the login window. This could technically be done as a screen saver, as some add-on authors have done, but I don't think any of those are in the official repo (I think asked someone to try to submit it recently, though), and it would be nice to have that option show up in core.
To make it more clear what the menu can do, we might also want to rename "custom shutdown timer" to something else like just "custom timer" which would be more accurate since there's more than just "shutdown" as a possible action.