Or just a cellphone that plugs into a monitor.
But having to plug your computing device into a monitor and keyboard to do any work is just a downgrade from a laptop that always has a monitor and keyboard. It's a bizarre portability trade-off that's even less exciting as laptops become thinner, lighter, and more powerful.
I'm typing this comment on a phone connected to a standard monitor, running a desktop-like experience [0] and it's surprisingly usable!
Hardware - Samsung S8 (2017), generic USB-C to HDMI adapter, bluetooth keyboard and mouse.