Why would you want to buy/take in exchange arms which are clearly substandard?
Because they are better than the ones they already have. They currently field the M-48 (which rolled into service in the U.S in 1953!!) although it is upgraded, and the K1 (indigenous)whos competitors are the T-72 and Germany's Mark 3, they are developing a K1A1 but they have yet to start serial production of them and they are also having difficulty with the 120mm gun as opposed to the K1's 105 mm gun.
I've read that they already have T-80's but i'm unsure if this is true and in what quantity. Either way, the T-80 is more capable than any of their tanks they currently field. So while it is sub standard compared to the new stuff it is still capable.
As for the other equipment, I couldn't say. Still, they're aren't stupid and wouldn't take the equipment if it was crap.