Yes it includes skyclub access along with a bunch of reciprocal lounges via the priority pass network.

To get into a sky club you have to show the Amex and a delta boarding pass (seat request card works.)

To get into other lounges you show your Priority Pass card, which you are eligible for with the AMEX Platinum, and a boarding pass.

If you travel a lot or have a lot of downtime before commutes it is definitely worth it.

As for spouses, you can add up to 3 additional cards for $75 and they all get lounge access. I put my wife and both of my parents on and then used each of the 4 cards to pay for global entry for me, my wife and my 2 kids. That's $400 right there before you even get to all the other benefits that have been covered above.

And finally, it goes without saying, but blend in and don't be that guy that ruins it for everyone. The sky clubs are a good place to hang out and it would be nice to keep it that way. I've seen pilots and FA's up there barely out of uniform (pilot with epaulets off, etc)...nuff said