I can see no other reason for the use of a bolt rig, other than anglers not being able to strike into a fish on a take. Surely striking into a fish is all part and parcel of fishing. A fish hooking itself, is that fishing ???, not in my book, but each to their own. I wonder why so many waters now ban bolt rigs ??
As for mouth damage, it's more likely to be a combination of all the above, i don't think it is down to just one factor.
A bolt rig can be every bit as efficient if not better than a strike imo.
and.... No need to strike when you can simply lift into em is there? which technically is also a strike, just a question of different forces applied.
Its the inexperienced 'striking' brigade that causes concern of most of the lip damage a lot of the time. Whereas a bolt rig works by pricking the fish under less pressure than a striking angler might, of course we also get anglers who also use bolt rigs and strike as well. But how do you know what size fish is on the end at depth or distance? Its not always a screaming run every time and guaranteed big one... applying the same striking force each time hoping its a record breaker, would rip the face from a pastie carp wouldn't it?
As to bolt rigs. There is a clear distinction between fixed, semi-fixed and in-line.
Fixed
Unless you can be absolutely certain there are no big species present, fixed is a no no theseday's as its potentially a tether rig should the mainline break.
Semi-fixed
Better and still self hooking but the lead clip systems are not fool proof. I have witnessed anglers super-gluing them on for fear of losing a £1.50 lead. I have also witnessed inexperienced anglers not pushing the swivel all the way into the sleeve so the lead cannot possibly eject (the hybid is an improvement). Not as safe as they could be if leads don't eject as intended. Putting them directly on the hooklink instead of the mainline... I kid you not!
Inline
These will also self hook over a distance or angle of take due to water pressure and resistance of angle. Not a bolt rig per se but they can act like one, especially close in when fishing tight lines and clutches.
There is a need for bolt rigs. They work and they work rather well if done right and can ensure a level of safety in the hands of both the experienced and inexperienced angler. It is not always possible or necessary to strike at everything. You cannot for example always strike at a fish coming towards you without first taking up slack line.
Ps. I have it on very good authority...
a very very safe (one component + lead) semi-fixed in-line lead system is
up for testing next year - No clips or anything and it can be free running too if you normally like to fish that way.