I could commute to the office every day with nothing but the shirt on my back and the phone in my pocket if my work-provided device were my phone. I would not need a backpack or briefcase, which means that for any errands or dinner plans after work, I don't fumble with a backpack. I already leave my preferred keyboard+mouse at my office desk.
If I needed to fly to another office for a business trip, same story: I could sit down at any desk, grab a spare bluetooth keyboard from IT (if there isn't already one on the bookable desk).
If I'm over at a friend's house for dinner and get paged, I could just ask to sit down at their desk and plug my phone in.
I would love to not have to carry a laptop around to all the places that I do today.
I remember being somewhat sold on this story by the PinePhone, but it seems like it might not be possible to buy one new nowadays.
Having just looked up the PinePhone again for the first time in a while, it does look like the Ubuntu Touch project is still alive and kicking, and compatible with some modern commercially available phones!
The main thing preventing me from having a non-standard Android phone/distribution as a daily driver is access to mobile banking apps - I'm yet to check for myself but as I understand, having an unlocked bootloader means that banking apps will consider the device "compromised" and will not work.