I agree and disagree. depends on what you are training. Honestly I don't see why you would need it for basics like sit/down and all that (this is just my personal though, not saying that's "wrong"). but when it comes to distance and high distractions (ex: off leash, squirrle comes by) you may need an extra tool (by no means do I mean slap it on and buz til the dog comes back). For some dogs it may allow for some extra freedom where as the opposite would be never letting them off leash. I think for some dogs, when done right to not stress them the trade off on slight stress to get the freedom may be worth it. Depends on teh dog and requries training.
Personal issue I have always had with recall reflected in the above. I am working HARD with Penny, taken a full class on just that, did the homework and am now doing an intense program and STILL having issues with her chasing things. We will keep working on training but we may one day need to look at the e-collar so that she can be allowed off leash in other places safely. Rocky's recall is crap and he eats poop so this has ment greatly greatly limited off leash tiem for him. Even fenced dog parks are horrible as they are full of poop.