The question is not whether you remember, necessarily, it's whether you successfully did.
Here is an example of where you might want to check:
Run multi-day classes with a combined total of dozens of different timed drills including hundreds or thousands of rounds and therefore dozens or hundreds of reloads, including mid-field reloads, dropping mags in the mud and pouring rain, reloading those mags as quickly as possible to get back to the shooting while taking notes, photos, video or audio during breaks...
Now can you guarantee that in all of the times you dropped mags in the mud while shooting a 50-round drill five times in a monsoon, none of those mags malfunction in a manner that will slow down the slide enough on an admin reload that you might mistake it for the feel of a round chambering, even though that did not happen and the round stayed in the mag somehow? Of course not. Sure, it's unlikely...but maybe you're now up on a solo timed drill in front of a guy you paid $500 to watch you shoot and diagnose any flaws. You don't have to take an extra second to check, but I'm going to, because I don't want a very simple mistake make me look like some kind of range bubba simpleton. Does it HAVE to be a press check? No, of course not. If you have a LCI, fine. If you are totally confident in the rather subdued Glock LCI, fine. If you want to take out the mag and check the rounds like you would on an AR, fine. But I press check because that's what I'm most confident in. I can do it visually or with a finger in the ejection port. It works and I don't have to screw with the mag, which I have seen cause more malfunctions than the press check.
As far as guys who carry for work, not every professional shooter I have known is in the habit of doing them but thinking of the conversations I've had over the years I would say a clear majority were.
Of everyone I have known who shot people in the line of work, the majority I have spoken to on the subject have been inclined to do press-checks at the start of their day and often right before kicking a door in, whether on a high-risk entry as a cop, or in Fallujah, or whatever. Sure, they're pretty confident they loaded the gun correctly...but man, you get that wrong once and that could be the end of your life.
Now if you're just some guy who leaves a gun on a table on a static range until it's time to shoot, I don't see the point. But I just don't do that and I have yet to experience any disadvantage to checking prior to any timed or scored or just plain important to me stuff I was about to do.