My recollection may be faulty; this was 10-15 years ago, (might also be colored by my affection for this particular relative!) but I was thinking they knew what the other units knew and then some.
A false impression. Their main gig is finding the enemy. Most of their training is (a) staying hidden, and (b) being able to report accurately on what's going on. Airborne and SCUBA training are merely for the insertion phase.
They don't do "direct action" commando ops, and they don't do unconventional warfare. They do have a challenging and stressful mission, but that mission is not a spec-ops one.
The perfect Marine Recon mission is one where they insert, gather information, and extract, all without firing a shot at the enemy, and the enemy never having even a hint that they were there.