I have, since just before lockdown. I now have four inches of salt and pepper hair at the roots, a similar shade to yours. And the rest of the growth is a dyed dark brown, shade #5, which I had done at the hairdresser's.
I do desperately need a haircut, taking four inches off the length would give me back a shoulder length bob. I trim my own fringe, and on my next cut, there'll be no dye left there. I reckon it will be another 12-18 months before I'm completely dye free.
The pros for me are cost, time and no longer having that false flat colour, as others have said. A block colour fools nobody. And I've never wanted to spend hours and £££ having highlights.
Cons, until you grow it out, you won't know how much grey you have, and it may be patchy (lighter at the front or the temples, for example). It also takes ages, you need to be very patient.
One thing I also noticed, my hayfever / allergies have all but disappeared. Just saying.
Cold turkey is the best way to go, in my opinion. Worst case, you are only one hair appointment away from going back to the dye. But that's a treadmill I'm determined not to get back on. 