It's commonly used in a renovation situation: fertilize and water well in early August to get everything growing, then hit it with two applications of glyphosate spaced about 2 weeks apart to kill everything, then scalp it as low as you reasonably can and seed with quality seed of whatever variety/varieties of grass you want to grow.
If you believe glyphosate is relatively harmless (as compared to a series of 6-10 applications of selective herbicides to achieve not quite as good as the same end result), it's easy to understand why people are inclined to declare bankruptcy on their mess of a lawn and start fresh. Applying it in August, you could have a high-quality uniform lawn by October. (If it's far from harmless, then the series of selective treatments might be better.)
Rototilling to start over just surfaces a bunch of latent weed seeds that are in the top few inches of soil always. To start over, you want to kill everything growing without disturbing the soil and surfacing the weed seeds.
Rototill is much worse for the environment. You have all the CO2 released from the effort. Plus bare ground that will erode away in wind or rain. Then you have all the organic matter in the soil you destory.
Or a little round up and plant grass seed over the top. Much less CO2, and the soil and organic matter stay in place.
I have a growers pesticide applicators license and a big jug of glyphosate in the barn. But I don't use it for that kind of thing because it drifts and damages the perennial plants I care about, and I just feel ... ehh.... about it. And if I grow stuff for market, it's good for pricing and marketing to be able to say it wasn't sprayed.
I have a rototiller for the tractor and I use it sparingly to break ground and then amend with manure and other organic matter, then cover in straw or wood chip. I get a lot of weeds (mostly crab grass and goosefoot), but that's just kind of how it is.
I have another herbicide which targets only grasses, and I use that here and there to try to control crab grass, but not for food plots.
