I could see it being used for specific usage handheld devices. For example where I work, we sell train tickets and ship cheap Android phones with an app installed for tain conductors to scan the ticket barcodes. Something like this could be done with some "generic cheap Linux device with a touchscreen and mobile connection" locked down to a custom built app.

Not sure if that ends up being cost effective considering how cheap you can get low-end Android phones these days, and how easy it is to find Android developers, but I'm sure there are some applications along those lines that would be well suited for the equivalent of "a Raspberry Pi with a touchscreen and smaller form factor".