I don't fully understand the excitement either. But I don't think learning to program is really one its strong points. Learning to work with input/output systems might be on the list but there are other platforms for that as well. I think the pi has a combination of low cost, relatively high processing power, and significant input/output capabilities that really attracts hardware hackers.

For learning to program I think I'd just go with a javascript scratchpad in a browser. Or for core concepts and less kludge, maybe just a node repl. I guess you could use a pi for that if you don't have a machine that you want to play with but that isn't why people are jazzed about the pi.