single pickup selector switches?

Can someone tell me how useful the tone shaping on a single pickup tele is? I know the pickup selector turns into a tone signal path selector in the traditional wiring scheme. Are all three positions useable musically? Doesn't the middle position that activates the tone control pot and the last position that wires direct to the output jack essentially do the same thing when the tone pot is all the way "open"? Thanks for the help!

On an Esquire (at least mine) full rotation on the middle position has the 250k value of the pot there. It's not the same as no pot in the first position evidenced by paint peeling from coated surfaces and bleeding from the ears! :shock: