Or the drafter may not be a very good writer! It's easy to fall back on legalese instead of taking the time to make something concise (see the article/video).
Right; there's some cargo culting in legal writing. Until a particular form of words has been tested in court, no-one really knows whether it will stand up.
If there's an untested standard form, most people won't want to experiment with a variation because if their variation happens to be the one that fails, there's a possibility of a negligence suit for not using the standard form.
If there's a tested standard form, even fewer people will want to experiment, for the same reason.