Some like them, some don’t. For me I run one on anything I intend to use for fire and movement in close quarters, (25yd and in) simply because they offer me another option to use as an aiming method if I’m in an awkward position, or need to shoot offhand or while injured. I would much prefer to use my sights, but reality dictates the options and is not always so accommodating.
I am not some hi-speed operator, nor will ever claim to be, but It’s one of those things I feel where having it and knowing how to use it properly is another tool in the toolbox you hope you’ll never need but its there if you do.
most of my personal experiences using one is during action shooting comps, where there have been several instances of time saved in close transitions or barricade work, translatable enough to real world defensive use for me to have one on my defensive guns.
if you want a vis only of decent quality, the sightmark lo-pro mini is surprisingly good, and not bad value. It at least survived my .308 and retained zero, which is better than airsoft chinese crap will do, and certainly a lot less than the prices you’d need to pay for dual-laser (IR and Vis) units.
get a green 5mw if you’re going to bother. significantly more visible in daytime conditions.
Less likely of a thing here on the hide given the knowledge of the average member, but don’t zero it to point of impact, it should be offset to your bore axis so that it is perfectly parallel, and then level with your PoA at a desired range (I use 25yd out of convenience, former mil friend uses 15yd)