For Ethereum Classic, Bitcoin Cash, and Horizen, I must say no.  I never hold them because those altcoins are not worth it to hold for me.

Focus on Bitcoin and if you can, put all your investment there for the safest investment among altcoins.  Ethereum (not the Ehereum classic) is might good to hold since it was upgraded to volume two I'm sure it's worth holding because of the unique smart contrast have which is very useful.

The comments above were right, practice first how to store your Bitcoin for a safe wallet and place and Grayscale isn't a perfect place purchasing or holding your Bitcoin.