I'm yet to see someone actually want it or use it. It's just additional annoyance to remove it. In general, Windows 10 made it difficult for power users, as they have a lot of disabling to do when they first install. I think they should have an "advanced" install setting with a lot of checkboxes, allowing you to enable full privacy mode, choose if you want Cortana installed AT ALL or not, etc.
On top of that, I really don't like having stuff that I don't use that's impossible to completely remove - as a minimalist it makes me uncomfortable. I have Cortana disabled but I'm still bothered that it's there, physically taking space and sometimes RAM (I can see the process) despite it technically not doing anything. I really wish Microsoft brought more control to the user back. I like Win 10, but I don't like how many things it forces me to accept.
I really don't care what Microsoft does with search branding as long as they make it search my computer FIRST rather than racing to display internet results. I want to change my mouse settings, not do a search for mice!!!