Not sure that applies to Martins, Gibsons etc etc who all use it. I guess the only way to be sure is to A/B two otherwise identical guitars, which is pretty hard to do. So many variables on a guitar, how does anyone tell which particular one is producing a particular sound
I have several guitars that include ebony, rosewood and maple FB's.
I have two Strats, one rosewood, one maple. The maple is brighter, twangier, or "quacks" better than the rosewood. The rosewood sounds slightly more humbucker-ish, has better sustain, and a louder attack.
My Gretsch '59 6120 has an ebony FB, and I really can't tell much if any difference other than perhaps a slightly louder attack compared to rosewood. Although I don't have another identical 6120 to compare it to, I do have two other rosewood Gretsches that are very similar to it.
For looks, ebony wins easily on dark colored guitars, and maple rules on light colored guitars, especially white ones. IMO
Just my $0.03. (inflation)