It's the same in a kayak. Water that most sensible people would be content to spectate from the side always looks like a series of small ripples to a Go-Pro. On the other hand, it would be very helpful with coaching, and you can film the others in the group doing things that you might not want to. And most kayakers are closet egotists who like to see themselves on camera.
Haha that last point though. I've gone down trails in front of someone go pro-ing (which I'm sure can be mounted to the side too, but aerodynamic they are not) and while in your head it's all smooth and totally railing those berms dude and hurtling skywards off jumps, the reality is sadly less than that.
Contour is another name to check, they went bust a while ago but I think may have come back from the ashes.
The 'F' in GF5 means it's got no viewfinder, hence is rather more diminutive size. The 16MP sensor in the G3 is really no worse than the ones in newer cameras, and the AF speed is already plenty fast so there's no great gain with a newer model. Basically you can spend a lot more money for not much more camera, and at ~£250 the G3 is a right bargain.
Ah, OK. That makes sense about the model numbers. I'm not disagreeing with you about the G3 being a bargain, by the way. I only chose the GF5 as an example because it was linked to on one of the pages you showed me. Ta very much.