To answer your question:
No. But....
Changing old habits is always a challenge. Older eyes started making my front sight fuzzy. So my transition to dots was necessary.
Presentation practice is key. I shot M&P open sights for years. But none were cut. My first dot was on my suppressed G19.
After years of shooting M&Ps, any Glock was going to be a challenge because of the difference in grip angle. I'd pull the G19 up, then find that Id have to tilt it down to find the dot. I got better, but it still feels forced. I then bought a gap/dovetail "filler" that changes the grip angle some. Works decent.
When I finally got an M&P that was cut and added a dot, finding it on presentation was pretty automatic.
Up close, in a standard IPSC target, I could be just as fast, if not faster, without a dot. (But I'm mostly aiming slide, or, a blurry front sight). So..depends on what you need it for. For in close self-defense... probably not necessary.
Where they absolutely shine for me is more consistent, accurate hits 10 yds and out. Fast hits on head or COM at 10 to 25 yards is easy.
I can hit 100 yds with the dot pretty regularly now. Just saying that to emphasize the consistency factor. Not saying I'll ever need that for a self-defense situation...but it's nice to know it's available in the tool bag
Bottom line, practice is key. And, if you're able to experiment some, matching the gun/dot combo to maximize your natural presentation helps. My necessity was my failing eyes, and I'm glad I did it.