BitcoinCash can be invested but not the best because it is forever a shadow of Bitcoin and uses only payment.
Bitcoin cash is very dependent to bitcoin on the price chart , it follows bitcoin so if you think that way I would say bitcoin is a better idea than Bitcoin cash , it has a bigger volume , more acceptance and you can cash it easier and in many different ways, now there are bitcoin ATM everywhere , some of them cash BCH too of course .
so bitcoin cash price depend on bitcoin price, if its true i am sure its not good portofolio for us. how could coins price depend on other coins in crypto market. it should be independence and able to create its own price with MVP .