I've got a Romeo Dot on a 16" bbl'd 5.56 AR that works well...took some getting used to, but I quickly found that it tracks coyote's far better than A2 issue irons. Too, with the long gun, I had no trouble using the Dot vs the clearly visible front sight AR-15 military type sight. As I've used scopes on most of my rifles since the early '60's and become used to the single plane of a scope's cross-hairs and the target, maybe that's why I've been successful with the carbine's Red Dot.
All of my handguns are iron sighted with the CC guns fitted with tritium night sights. Only one, a Sig P226 had a light and that's a bedside gun. I don't foresee a change based on my experience noted below.
As to handguns, & just shy of 60 yrs of the FRONT SIGHT FOCUS mantra, makes using a Dot difficult with it's focus on the target difficult for me. Tried a Dot for over a week exclusively with considerable frustration and no real improvement. My draw/presentation movement in defensive shooting ended up with a search for the Dot. It just never came together for me. And later, returning to irons, I found that my front sight focus had gone to the dogs in that brief lapse.
At 77, I've been wearing glasses since my late 40's and have had no problems maintaining speed and accuracy with irons. I think, based on my admittedly brief trial with the RD, that to be successful, a shooter has to commit to one system or the other: glass or irons.
YMMv of course. Rod