Yes we need altcoins. First of all these bitcoin cash and other bitcoin forks not interesting for me. Their only one speciality is have bitcoin in their names.
There are too many altcoins and all of these for some other fields and they have different purposes. People can create some altcoins for different bussines spaces. Also
they are using new technology and new codes in these altcoins systems. ı believe we need all of these altcoins . People need different coins because all the people trying to find different coins with different features. They can easily choose the best coin after their research.