hoosier:
Seriously, I would like to hear your explanation, too. Curt.
P.S. Floater, welcome back....
I'm not curt but...while they are similar in that they both involve an overhead the environment is completely different in all other respects. Just a few differences off the top of my head...
While inside the wreck is overhead, the wreck itself is usually in OW. OW that can be pretty fickle when it comes to waves, current and boat traffic. The OW portion of the dive can be significant and I've never heard of anyone getting blown off of a cave. Consider also that in some areas, wrecks in significant current are dived from a "live boat"...sort of a a drift dive and a wreck dive combined.
Wrecks can have cables, wires, sharp edges with decaying and collapsing structures where caves are usually pretty stable with many edges nicely rounded by water flow.
Many caves (though not all) have enough flow to clear away silt once it's stirred up where some wrecks may stay silted out for days once messed up.
While there are complex cave systems and cave divers dive things like flooded mines that can be very complex, you can almost count on complexity in many wrecks.
Popular caves often have permentant lines for navigation where most wrecks don't. Even running a line in a wreck has different considerations because of those sharp edges and things that potentially move.
In most cases decompression is conducted outside of a wreck in OW where in a cave it's common to do most of the decompression in the cave. In a cave, you can't always ascend directly from one stop depth to another and there mayt be less of a chance of a square dive profile in the first place. You could potentially even have to do decompression between deep and shallow portions of the dive on the way in...you can only go where the cave goes and it can make for some pretty strange dive profiles.
I suppose we could go on but that should be enough to show how completely different they can be.