To me it all centers around: Was BYOD optional?
If they offered a company device and you refused, then i say you are on your own.
If they didnt offer one but you NEED it to do your job, then i say they are on the hook, as well as tax credit ramifications.
If they dont offer and you only use it as its a convenience to make your life easier, then again, you are on your own.
Furthermore, if you are optionally using your device for office work, they get to mandate policy on its use, up to and including MDM type control.
BYOD is just a bad idea. Companies should give employees the tools they need for their job, and forbid personal devices.