Alright then. I haven't actually done the numbers here, so let's unpack that a bit. This should be interesting.
Let's assume that you're going to buy out a Maritime for an Ally with money. I believe that the Maritimes give 2 food to the Capital and one food to the supporting for Allied? Plus lux, of course. In a 3 city empire, that's equivalent to 2 land routes in Classical - and a good Land Route at that, since the value of the lux is at least 5 gpt.
For this, you pay something like 1000 gold for 90 influence? That's a cost of about 11 gpt at 1 influence loss per turn? Worth around 2 good Land Routes, which is the return you get. Initial Allied costing is waived against the initial hammer cost of the route/s. Presumably, you would instead put that into military units to do favors for your city state friend.
Seems equivalent to me.
You can either put the extra 2 Land Routes into gold to fund CS gifting and such, or put them into food. If your routes are good, Maritimes should return well. If they're bad, go for the food routes. Break point seems to be about 5 GPT per route being equivalent to about a 4 food route (for a small civ).