Lasers and reflex sights have some uses. Not as something to rely on on a SD/HD gun.
Why is something that allows for faster target aquisition not something to rely on for a SD/HD gun? I understand that RDS can fail and that's why you have BUIS, but why is something that the Army trusts to work something that I shouldn't trust?
It’s not so much a question of time, but of position, possible injuries (can you even raise your gun for a ‘proper’ sight picture), etc. If you’re behind the sofa, how ya gonna check out the view – look over the top of the sofa, or peer around it closer to the floor (I know which option I’d choose). If I’m trying to present as small a target as possible, am I going to be able to use a red dot in that position?
You expose maybe a half inch more using a RDS over irons. If you want to use the BUIS as your sight plane to lower your profile, the difference is even less.
‘Spose your home invader has struck the first blow – mebbe your arm is injured to the point you can’t raise it?
In this case, irons vs. RDS doesn't matter, it becomes Iron/RDS vs. Laser. If you can't use the RDS, then you wouldn't be able to use irons either.
Lower profile doesn’t matter much with a pistol, eh…CC much?
I listed concealed carry and lower profile separately. Easier to conceal is the bigger issue. The low profile I was referring to is low profile while sighted, which doesn't make much difference when using a pistol RDS on a milled slide. Take a cheapo reflex and put it on top of an aftermarket rail on a shotgun and you'll change the profile a lot - enough that I had to adjust shims and buy a higher cheek rest. On a pistol, the difference isn't nearly that big.
Concealed carry I do agree is an issue, depending on how you carry. IWB might be a tad tougher. OWB you probably wouldn't even notice. Pocket carry a RDS would be terrible (I can pocket carry many compact autos in my cargo shorts hip pocket, but they barely clear the pocket with an easy draw).
Ya'll can carry on the theoretical arguments and perfect world scenarios...I'm still trying to wrap my head around a Reflex sight on a SHIELD
I don't see how the RDS being faster than irons is "theory". It's been proven to work by pretty much every review I've read that started with "I thought it was just a marketing gimmick until I started using it." Even still, I think you're getting wrapped up in someone putting it on a Shield. If it fits and works, why not? Personally, I wouldn't put it on something I'd pocket/ankle carry, and that's the only reason I'd get a small single-stack.
ETA:
To that end, I assume the discussion would also be to determine what's practical / feasible / desirable, and what is bling.
This is true. However, one cannot deny the advantage that a RDS provides in terms of speed compared to irons. You have to start there before asking yourself if it is practical or not. I would not consider the RDS "bling", as bling is something shiny with no real use. The RDS has a real use. It also adds to the profile of the pistol and incurs cost and time invested (which is not mutually exclusive with training). The questions that should be asked to determine if it's practical or not aren't the speed comparison with irons, but: 1) whether or not you can carry it with the added size, and 2) whether or not you find the cost and time investment to be worth it.