'Other than having the ability to make the SRB's fall into the ocean, rather than on someone's house, is there any other reason why they don't launch shuttles from the drier Nevada desert rather than the tropical Florida coast?'
Not really. Canaveral had always been there so that missile tests could drop harmlessly into the Atlantic so it made sense to keep on using it. As Ian R 1 says above, you also get a small extra kick into orbit by moving the launchpad closer to the Equator.
The Shuttle was originally also going to fly out of Vandenberg AFB on the Californian coast to put military satellites into polar orbits - the SRBs dropping into the Pacific. Although the USAF had been the biggest influence on the Shuttle's final design, they dropped it like a hot potato after Challenger and went back to big expendable launchers.
Which in a way was a good thing. The Soviets were terrified the Shuttle could be used to lob a huge nuclear weapon over the North Pole as a first strike weapon. Scrapping polar flights solved that little Cold War nightmare. But not before the Soviets bankrupted themselves by building their Buran Shuttle capable of doing just the thing they were worried the Americans were planning.
Oh how we miss those days of bat-shit insane paranoia.