What do you mean, he only accepts BCH as payment?
Bitmain only accepts BCH for the current batch of s9 miners. I think you can purchase other equipment with other means, however.
https://coinspectator.com/news/75338/bitmain-now-accepts-only-bitcoin-cash-for-their-latest-mining-hardware
Yes, my bad. I didn't see it first. I edited my post. Thank you.
Although, he prices it mainly on USD. If he would price it ONLY in BCH/BCC... now THAT would be interesting.
People rarely price things in cryptos due to their fluctuating value. Also you have to time the markets correctly to buy things with cryptos. I expect there is an increase in commerce with cryptos when the value is rising, but I haven't seen any stats on it.