Jolla's Android emulation is unreasonably excellent, one of their technological gems. If other Linux devices ever lift off, this will be one of the killer features that Jolla can license out. (And why not? I'm absolutely in favor of vendors selling Linux software.)
As for Sailfish - it still offers the best, most consistent, simplest UI/UX of any currently available mobile device.
Edit: and I don't have to root my phone. I can SSH into it (or use the included terminal emulator with my Bluetooth keyboard) and I have access to the full Linux filesystem. For app development, there are no hoops to jump through (like Apple's developer license).
Mobile Linux is already here, and it works!