Long-term holding is not for all people, as short-term trading is not good for all too.
Both have their good and bad sides. But, if one has the patience to hold for long when he knows the project is solid, then ha must go for it.

Trading altcoins is profitable for knowledgeable people. I see hedge funding (like the upcoming Ferox Advisors project) as a good method for profiting. But, is only suitable for people who have the courage to trade for the short term, instead of keeping holding their assets.

So, there is nothing wrong with holding our alts if the project(s) are solid.