I do, because I'm not a restaurant, and I don't buy enough meat for one or two servings of hamburger. If a restaurant's been around long enough and has enough turn over, they won't have my problem, but a place could want to freeze for time reasons, or to help with getting a gnarly crust by cooking it from frozen, etc. If you're freezing with the kind of thing the NYC sushi guys use (http://www.nytimes.com/2004/04/08/nyregion/sushi-fresh-from-...), and defrosting properly, a truly great hamburger could easily be made from a frozen patty.
I've never heard of a good prefrozen hamburger patty unless you're getting something from Snake River Farms or something along those lines (they ship frozen meat). I freeze my own.
Same goes for fresh bread. Maybe they want to serve pastrami sandwiches in Manhattan, but the best rye bread they can find is in Detroit, and so they have their baker freeze the bread and ship it over. It's not that the bread is better because it was frozen, but they're able to get better bread because they could freeze it.
https://www.dti.dk/_/media/66980_Effect%20of%20packaging,%20... (PDF!)
Freezing food has a stigma that it doesn't deserve if the freezing and thawing is done with care. As I mentioned before, the best sushi restaurants in Manhattan all freeze their fish and store it in extremely cold freezers, and there's no significant detriment to quality. If Shake Shack wanted to do so, they could freeze their patties, and they'd still have one of the best restaurant burgers out there. They certainly would not be freezing their meat in the way that was done in that burger paper, nor would they be using meat of that quality.
Long story short: freezing brisket, not a great plan.