Yes it is still worth, but not all altcoins, just few valuable ones having good potential like Ethereum, Ripple and Litecoin for example. Such coins have good value and developpement and their communities and volume of trading keep growing up with time, so holding them is likely very profitable for the long run.
Yes I agree. It is still worth it to invest in altcoins but limited to a select few. Particularly those exceptionally performing coins in the global market.
A good indication of exceptional coins would be a strong and growing community, cultivating a healthy environment, products with real world application, with road map fulfilled.