Killer apps for me are physical keyboard, GUI bootloader that can do multi-boot (so that I can switch between one of the mobile distros and a Xorg based i3wm desktop, because there's no way mobile distros will ever have reasonable performance for convergence use), convergence with accelerated video playback and a reasonably smooth web browsing, possibility to run Arch Linux ARM as is with access to the entire package repository of software (that is not ad laden or spyware by default) on my fingertips, and full control over the security of my phone by being sure I can run my OS without the CPU ever touching any code on any modifiable storage inside the phone,... :) That's already there with original Pinephone.