Nobody is gonna walk around with xbox one or ps4 controllers in their pockets, it's a complete waste of time bringing console/pc games to the mobile market.
Never said they would, only that "I don't think their intention is to make us play streamed console games with phone controls."
But if the controller gets small enough, foldable or integrated in the phone case, some people may use it on the go. That Nintendo patent for a case transforming your phone into a Game Boy comes to mind as well. Besides, people carry their Switch around don't they? At least when traveling for longer distances.
Personally, I could see myself use game streaming on my phone if a great controller was made. At least as a second screen solution at home when gf uses the TV.