Almost android device once they became more powerful and had root, around after 2016 is when only root matters.

Full Linux CLI, all the game systems of the 90s playable, all the hardware devices of the 90s emulated but much better (the Pokédex app was very good, TI emulator, etc), OTG docking for wired devices or you can use BT for hardware. They can do 90% of what your current phone can do but everything is a bit slower and worst, so using it as a dedicated device for various purposes like a Linux man page app at your computer, a device to game on, attach a controller, spares your non easily replaceable battery, if you have an iPhone and didn’t jailbreak, having a handheld Linux computer in your pocket is convenient to easily use CLI tools and SSH/MOSH.