When playing with cultural victory disabled in Civilization VI, do I have any use at all for tourism? Does it impact the game?
There is no other use for tourism other than achieving a cultural victory in Civilization VI.
Culture still has use (for policies, etc.) but the boosts it can provide to tourism are also useless with the victory condition disabled.
Additional: It is worth mentioning, as noted in this thread, that in Civ V tourism had other uses such as your happiness and trade, especially when ideologies were being chosen. However, in Civ VI that mechanic is not present.