maybe you don't need jump, but the rest of us would like it. It harms nothing and can only be helpful.
The only reason anyone EVER uses to attack it is "it's not "final fantasy" " or "People will jump around like idiots all the time."
To the former I say "Final Fantasy" is whatever the makers want it to be, and to the latter, I repeat, "A few idiots that act immature is not a reason not to implement a useful function.
Also: The world we have now was not built with jumping in consideration. The new world will be. When that time comes, you WILL have reasons to use it.
As long as it's not grossly unrealistic (e.g. jumping 4 times your height like Mario), jumping is a harmless function that can be useful when the world is designed with the understanding that the function exists. If someone wants to act like a retard with it, just blacklist them, ignore them, and move on. They'll stop as soon as they see that nobody wants to associate with them.
FINALLY, even in the current world there are still a lot of small ledges you can't simply walk off, rocks that are annoying and could be vaulted over if you could jump (A second saved is a second saved, I don't care if you think it's too small a benefit), and in particular, if you could jump, there are certain parts of places like Limsa Lominsa where you could get around much faster.