Because
etherum
Bitcoins
Litecoin
Bitcoins cash
Are the ones really making the news...
Everyone's own thinking May differ but it's for an individual to decide what to invest it
I also believe that Bitcoin and ethereum are the best cryptocurrency to invest in. When we look at it, these two crypto has already established in the market. Including litecoin and Bitcoin cash is a bonus in the criteria.
I am sure that each guy what deals with the cryptocurrency must have Ethereum and Bitcoin in his portfolio. Nevertheless, there are many cool tokens to invest in also.