I think a red dot is darn near mandatory for sub-hundred yard work on fast moving targets that don't want to git shot. Slinging up and playing DCM marksman is a necessary skill, and great on stationary targets. But suppose the zombies are the fast kind?
For those that don't know (and I didn't, 10 years ago, maybe less.) a red dot sighting system Give you a little window to look through, in lieu of iron sights. When on a little glowing crosshair or dot is visible to you. When zeroed, that dot is where the bullets will hit. At 100 yards that dot seems kind of big, compared to the target, but it's small enough to get the job done on center mass shots. Remember the movies in the 80s and 90s when someone had a laser mounted on their gun? It looked cool and the laser got smaller and smaller over time from the one on the Terminator's .45 long slide as BIG as the slide, to pen-cap size today. Well, the military doesn't use visible lights like that, but the red-dot LOOKS like that little red laser dot from the movies to just the shooter looking through the window. If the red-dot optic is turned off, it's just a little window, and often the idea is you can see and use your iron sights if you have to with the scope mounted. There are other scope types out that illuminate the reticle or cross hairs as well. Ain't technology grand? Our grandfathers in WWII, sniping with long and narrow telescopes with 6x power would either laugh at us or say "gee whiz! lookit that!" Probably both.
The sub-100 yard role is well addressed by Kim Du Toit's preparations for Grab N Go SHTF situations. He is an even MORE a crotchety conservative than me, and it looks like he is sticking to iron sights. Come to think of it, I've never seen Kim talk about these new fangled sights at all. And I know Jeff Cooper jokingly talked about needing battery bearers as much as ammo bearers and water bearers in today's modern operationgs.
And for comparison, the Leupold CQ/T: