I think that it would be better to say that, “whether or not you can parse XML using regexes ... from an engineering perspective that is not the point.” When you are developing a piece of computer software that needs to process an XML file, the single most important consideration that you have is to minimize your exposure to project failure. If you have at your beck and call a package of software that accomplishes a particular task (as evidenced by its ability to pass 15,385 (or somesuch) internal self-tests, and if you can get all that just by uttering the magic words, use XML::Twig, then, “point, set and match!”
This is the very same reason why there is a viable and important business in making pre-hung doors and even, in some cases, pre-finished walls and houses. At the end of the day, you just want to deliver results. You want to collect your final check, go to the pub, and not worry about being interrupted as you get a wee bit pleasant, because you know that every promise you made to your customers was kept ... and that you made a modest profit doing it.