On the Pinephone, and all other ARM-based Linux devices, we're still running applications like web browsers that were written expecting to run on multi-core I/O monsters with lots of RAM, beefier GPUs etc. (the main exception being the main GUI shell... it would be so much worse if you had to boot the phone into a full Gnome/KDE environment) We're still in the late stages of getting the pile of software that is a typical Linux distro running at all on a mobile device. Then assuming these devices get enough traction, you'll start to see more effort put into mobile-optimized software.