My answer to the "why bother" question is simply, "because it'd be interesting".   The trick with the wireless probes is making the transmitter small and waterproof.  That's the problem I've seen with them.  The transmitters I've seen are about 3/4 the size of a box of playing cards.  I would have several uses for these besides brewing and let's face it.  Wireless = cool.  Done and done.  
 
Cheers,
Stevis