I use the back buttons as alternative shoulder buttons.

My right bumper button broke and I can’t find cheap replacement daughterboards, so bandaid it is. I can’t just solder in a new switch because the leads on the PCB broke. Seems to be a failure common mode for the bumpers if you ever hit the corner or drop it. The way the bumper is designed transfers the full force directly to the PCB instead of to the shell or any actual structural component.