Depends on who you are. I think it's important for newer umpires/officials of any sport to get a firm grasp on the rules before worrying about mechanics. Once you have that, it's important for your intermediate official to get a firm grasp of mechanics, in order to most accurately apply their knowledge.
A rules guy that is always out of position is of no more use than a guy who is in perfect position to not know what to call.
That said - as far as posts here go, for a reasonably experienced official, MOST of the posts here about mechanics are not news to me, whereas we can always learn something about the rules from interesting situations. On the other hand, when a post here DOES reveal something new to me regarding mechanics, it is probably of more value to me than the rules decisions.
Probably completely failed to answer your question, but that's my 2 cents.
