Bitcoin cash is a legit fork of Bitcoin, with a different model about how to attract transaction volume. They have every right to seek merchant adoption, and if they pump, why should you care?
Bitcoin harmed itself last year when it said No to segwit2x - as a result lots of merchants dumped it as a payment method. Other alts including bitcoincash are going to try to fill the void. What did you expect?
I do not see any battle between the original bitcoin and bitcoin in cash. What could be the manifestation of their battle? Of course, bitkoin cash competes with the original bitcoin and I think it's normal. Bitcoin should be improved. otherwise it will be replaced in leadership by others, successful coins are sick.
Bitcoin had faced numerous issues like transaction speed scalability etc. That's why forks happened since October as Bitcoin Cash, November as Bitcoin Gold, December as Bitcoin DIamond and early January the Segwit2x.
Seems we can't feel their battle but we just felt that Bitcoin stayed on $10,000 or below for almost 3 months now and Bitcoin Cash continues to surge.