If you find that you have the most fun on Runescape by doing things as efficient as possible, then yeah the staff (or any other non-optimal content) is probably not useful to you.
I do not always find that to be the most fun for me. So I (and others like me) are going to find value in non-optimal content. I'll probably get the staff eventually because elsewhere in the game I tend to get fire runes on the side, while getting nature runes annoys me. So I'll use the staff to make my overall enjoyment of the game better.
New content does not have to be a new best way to do something (especially not when it's just a drop from a mid-level boss, by the way). It can just be a different way of doing things.
More points:
Players don't start the game able to use the best-in-slot equipment, the fastest routes from A to B, or the fastest experience rate activities. They have to work up to those things. This staff could very well be a stepping stone to bigger and better things.
Will it be a popular staff? Does it hurt being in the game? Did it impact the normal development of OSRS content? No to all of those. So, the worst thing that this update can do for an OSRS player is be content they don't touch. That's nothing to complain about; for the person solely interested in optimization, a huge amount of content in Runescape is in fact content that won't be touched.
07-May-2018 15:25:16