If you want to bend the rules to make diversity relevant, that's nice. But you're not playing the game as written.
Personally I'd love to house rule elemental differences, but at least I know it's a house rule.
What rule book are you reading? When I read pages 254-255 of YS, where it goes on about the different uses for the different elements, they clearly delineate differing uses for each, where they are better at some things than other elements. No where do I see anything that removes that. No one is house ruling a thing when it comes to different elements satisfying catches or enabling certain aspects.
Veils, as one example, are the "special province of spirit magic.". That's not a house rule...that's "as written". You certainly aren't going to hit me with a "Drenched" aspect with fire or earth. I can see some correlation between earth's gravity effects and air "pushes" or pressure, but it won't look the same, feel the same, or have the same scene effects.
If you want to disagree and run it your way, believe me I'd be the last to tell you you can't, but the idea that elemental differences are "house ruling" is just plain wrong, as is telling me I'm not playing the game "as written".
Now, if you are referring to the sidebar where it talks about justifying electricity via earth or air, sure it opens the door for varying justifications, but no where does it invalidate different elements...at least not that I can find.