It's a mental thing. The phone is the doorway to all the things, and the reader is the doorway to reading. When I'm being intentional about my phone usage (not always, but most of the time), I defer to devices that are focused.
The phone's reader app is quite good. I use Librera FD and quite enjoy the scroll mode.
But then I'm subject to the bright screen, all of the colors, all of the notifications, and everything else that the phone brings. The calm of the X4 is quite nice.
On the reader, the entire thing is one reader app. On the phone, the reader app is one of many that lives in the phone. Easier to switch apps than switch devices, so I guess it's easier for some to stay away from certain activities by having a dedicated device for certain purposes.
