QTOFFER, you are hardcore!!
Also, because the tub is lower than the sink, and likely lower than most tanks, you can shut off the water flow and just allow the syphon to run by itself if you are concerned about wasting water. In the tub it is also easier to put a container under the faucet and catch the tank water for houseplant watering.
I am too fond of my tub faucet, esthetically speaking, to swap it out!
PK Tester, as long as your faucet has some sort of threading on the end you can find an adapter that will connect to your python so it will work. If it is not threaded then you are out of luck, unless you can come up with some clever modification.