Without being able to present this as fact, I've been told by a couple of reliable sources who supposedly know this (and I believe them) that the Casa Bar business itself is leasing the place in which it does business. In fact, I was told that they had spent quite a bit of cash remodeling the place, which can be questionable if you don't own the building. I've heard of people being screwed over when they make significant improvements in the place and then get the rent raised to uncomfortable levels at the end of the contract. My understanding was the contract was a standard 3 year commercial lease, but again, I can't confirm it as truth.
Therefore, as the ad was presented, it wouldn't be the building or space, I don't think.
I know the guys (acquainted with one, have met the other) who own another expat bar in town (edge of Recoleta as well) that is very popular with the college crowd, who are leasing their building, but on understanding with the building owner (expat - I'm acquainted with the owner) that there will be plenty of notice of any kind of change in terms. They have done some work, but basically left it close to the original condition.
They do a good business. They don't cater to expats (which I also don't think is a good market in Buenos aires) but rather to college kids who outnumber young partying expats by orders of magnitudes and are plentiful in the area.
Casa Bar is quite a bit more stylish, upscale, I would think is targeted more for local and visiting working adults and some of the younger crowd. When it first opened, I went there a couple of times with buddies to watch a football game and it was OK. It was fairly crowded in those occasions. A year or two later I went back once or twice and it wasn't very crowded. Don't know if that's significant or coincidence.
I think the other guys' business model is more successful though. They deal a lot with local crap from police and government inspectors, but the money is well worth it. If you have the volume and run the business smart, following the money, you can certainly make a killing here. Just depends on whether or not you want to deal with it.