As long as it doesn't eat through the can, I don't see a problem ;).
Because your beverage touches the outside of the can on the way to your mouth?
Just rinse it off first. Most cooler water is pretty gross anyway.
Use your pool instead of the canals?
Mmmm. 80 degree beer :) Florida pools get very warm.
I got it: build a soda dispenser like in the OP, except make it fill with rainwater, and insulate it. Assuming the rainwater is cooler than the ambient air it should keep the cans cool without requiring power. As a side thing you could attach either solar or wind-power to a peltier to cool the thing even more.
It's tangentially related, but my grandfather used to tell me stories about growing up in Florida in the 30s. He and his brothers used to homebrew beer, and in order to keep it cool while it fermented (and hide it from their parents), they'd burry the barrel in the side of a ditch.