Can’t speak to the usefulness of a foot mouse, but a cheap set of 3 USB foot switches is a game changer, literally.

For tactical shooters I bind lean/peek to the side pedals, and set the center pedal for voice communications.

For solo gaming, you can take your obnoxious overlay commands, set them to impossible key combinations, and then bind those combos to the foot pedals. No more accidentally opening up the Steam or AMD overlays, but they are still there if you want them.