Granted, given the quality of the Supercharger network, the likelihood of needing to fallback on CCS is small. Still, isn't more options better than fewer, if you manage to get yourself into a low battery situation?
While I think the SC network is better in just about every way today, I do think EA/EVgo/etc will catch up or even surpass (350kW, 800volt chargers aren't unheard of, for example) in the coming years. I've never been a fan of proprietary options--e.g. hate that Apple sticks to Lightning when everyone else has standardized on USB-C. I think of this as fairly similar. And look at the innovations taking place in the USB-C charging space vs. Lightning.
While SC is the best experience today and in the likely near-term, what about down the road? Once literally all the other car brands ramp up their EV production and all using CCS, eventually their combined sales numbers are going to dwarf the "odd man out" charging standard Tesla. This does worry me somewhat.