[electromagnetic]

Style, frequently, should be personal and 'learning' it often betrays the original writers intent. However, you're right. Strunkn and White were writing, primarily, about style and in such it is more akin to a recipe book for writing rather than it is a dictionary for spelling. If the book helps you in one specific area that you yourself desired to change, then it's likely been beneficial.

Having said that, Strunk and White's book is an abomination of self-contradiction. I can tell by your writing, albeit only a small snippet, that you don't follow their teachings religiously (as some do; IE the Grammar Nazi's - a little knowledge is a dangerous thing). You use your own style for parenthesise (dashes rather than commas), likely one you picked up and liked, and one the Elements of Style suggests is wrong (at least from as much as I've managed to read of the text).