Yes it is,Altcoin is next to bitcoin and also it is growing just like the bitcoin.Because altcoins were becoming popular and known in the world,many are users and traders thats why the economy of altcoin is growing and increasing.It is very reliable now and helping our world.Altcoin is worth buying because of high price and value as of now.
Only a few altcoins are worth to buy for future use. And rest of the altcoins are worth to do altcoin trading. You can earn money with investing in altcoins. Future use I will prefer eth and waves. Zcash and Monero also good but now these coins are losing their value, and people are not interested. LTC is also good coin to invest.
Zcash and Monero are long term players and you cannot expect that they will make you rich overnight and if you want to make money from it then you need to hold it for a very long term and for that you need to have a great level of patience as people who invested in those coins have already made huge money out of it and even if you invest in it right now I am sure those coins will not disappoint you in future.