Cordura & kydex both are objectively better than leather imo, but I confess I just prefer leather for everyday use for most things. I have a few exceptions, such as a couple kydex holsters for small glocks, neck peck sheath, etc, but overall I mostly stick with leather. That said, I do realize that that's just the old fart in me coming out; letting my personal preferences take priority over objective superiority.
Leather takes more maintenance, it often has a shorter lifespan, it's more vulnerable to heat/cold/elements, it's heavier, and it holds moisture. And due to those traits that leather has, things carried in leather tend to need more maintenance as well. Recognizing & accepting that increased maintenance is just the price to be paid for my choice; not the most practical choice objectively I realize, but a price I'm willing to pay for the benefit of using my preferred option.
At least I recognize that my preference is just that - personal preference; and not something I'd intentionally try to sway others toward.
"The best a man can hope for is a chance to prove that the good lord didn't make a mistake putting him here in the first place." - Will Sonnett