I'm not usually interested in altcoins myself, but I can see how people can enjoy them. Most altcoin "investing" is a lot like gambling. I can see how trying to navigate and manipulate these tiny markets could be fun for a lot of people. These pump-and-dump altcoins aren't really competitors to Bitcoin: they're really a way of using your bitcoins to gamble. There are also a handful of technologically interesting altcoins like Monero, which I think are very useful for testing new ideas that might one day be incorporated into Bitcoin.