I feel MDS has made a valid comments for some one interested in cave diving in the UK .tad inappropriate on a diving forum
Dry caving lets you build knowledge of systems to let you pass through dry passages to get to the sump most good sumps are well into the caves. You also understand how the cave works as underwater is much the same as above it.
In some ways this is why the CDG likes to draw its membership from the caving community (the training is also free other than your subs).
If you are interested in cave diving in Florida then not quite as releavent although a cave what ever the size follows some basic rules.