Though you don't make the same money on entry fees, 2 "yachts only" docks will keep 8 luxury hotels filled. This is a handy tactic on small islands or short games.
As nice as airports are, the take up a lot of valuable space, money, and building time.
If any of these constraints are squeezed, the docks are quite handy.
Tourist docks are also useful when you have slow economy growth. By the time you "slap down" an airport, your tourism trade could collapse under mounting maintenance fees. A tourist dock will keep those hotels paying while you are building that airport monstrosity.
Now that's why I play with a huge island and an open-ended game.
But before I start my tourist trade I make sure I have enough from industry. Green Thumb trait really helps keep things clean while the Financial Genius, Capitalist Rebellion (or Election), and Self-made Man cancel out the negative effects of Green Thumb. But if I want workers, I choose the Professor background. I never want to start a tourist trade without a good financial foundation from industry, so tourism comes late in the game usually when my industry is hurting from internal problems such as lazy teamsters and dock workers.
Usually I build the airport and than build the hotels, pubs, nightclubs, etc. But the trade benefits from the airport are very nice before the hotels get built.