sometimes having an lalr parser generator tell you where the ambiguities are in your grammar can be a useful step to understanding the language you're trying to describe. you're probably right that once you do understand it, you should throw away the grammar given as an example and write a new one ;)
Sure, especially for anyone not used to writing parsers using a parser generator is a good way of validating assertions about it. But for that parser, just starting by cleaning it up would be a big improvement irrespective of formalism. Even if you get an unambiguous parser, if you can't read the grammar you'll end up with nasty surprises anyway...
