Your not overthinking it - it's a great idea!! What macro would you use? Do you have the back of your tank painted?
I can see something like that growing... It would look like a big hedge on the back wall.
If you don't mind the look of the egg crate - it's a wonderful idea.
The microbubbles aren't something that is bad for your fish or corals at all.. most hobbyists just don't like the looks of bubbles in their tank. One thing about bubbles is that when they break at the surface, a tiny amount of saltwater gets sprayed everywhere - and that creates salt creep.