I didn't lock the brakes up, but the previous owner may have. I just bought the Jeep last week. It's not a very large spot, and the tread looks fine. Yeah, I get that it's only 1/2", but it's still 1/2" more than I had. I'll eventually get a lift and bigger tires, but I'll wait a while on a big project like that. I don't have the cash or the time right now.
To answer your question of, why only go 1" bigger? Mostly because I don't want to spend the money regearing, lifting, and adjusting my Jeep. If I need to buy new tires for this Jeep because of the flat spot I just want to buy the biggest that will fit on a stock Jeep.