Correct me if I’m wrong, but it seems to me the only difference between the Challis bushing and other bushings, are the tool used to tighten them. I realize they also use the O-rings unlike factory bushings but are there any other differences?

1911 grip screw bushings always seem to be stripped. Is that because the grips are bashing them during recoil? I just fixed a bushing yesterday using red Loctite.

Yes, they use a nut driver/socket instead of a screwdriver or bushing driver.

I rarely see stripped bushings, either inside or outside threads. What I DO see are bushings that unscrew from the frame when removing the grip screws. I use red Loctite as well. Having the appropriate taps to chase threads is mandatory.