When you use spread sheets a lot, much of what makes you productive is that you know exactly what Excel will do. Like yes I know it's going to try to increment when actually I want to fill this column with 1s or whatever, but I can hold ctrl and override it and all is good.

With copilot, you will never be sure what it's going to do. I feel like it would slow me down even if it guessed right 90% of the time.