Altcoins can be extremely profitable, however at the same time, many can result as worthless.
Personally, I find that if you identify an alt coin that has a product which you truly believe in, and think it has potential to change the current status quo, it is worth investing a small portfolio of your portfolio for a long-term hold. If you feel there is strong potential in the underlying token; I see it as a more valuable investment than bitcoin itself (just my opinion)