I think the BNI transaction fits exactly with the kind of returns that Buffett is focused on now and has told everyone he is focused on. He was able to put a ton of money to work that he most likely feels will generate pre-tax returns on capital in the high single digits or low double digits at best. If you add in the potential benefit of using float he would increase his returns by a couple percent over time.
This deal isn't appealing to me from an investment standpoint, but then again I don't have a lot of capital (unfortunately) that needs to find a home. I think the error people continue to make is looking at what Buffett is buying and not understanding why he is buying it.