Indeed as previously posted...has never been such a thing as Diamond Plus lounge. You are probably referring to the Concierge Lounge. A year ago Diamond Plus were kicked out of the Concierge lounge. The Diamond Lounge (now being changed to "Crown Lounge") is where Diamonds, Diamond Plus, and Pinnacles go for a loyalty lounge. Suites Lounge (and what is left of the named Concierge lounges) are for GS and above, or if numbers low enough in total...Pinnacles not in a suite invited in (but that is not a given).
We prefer to use our drink vouchers at the various bars and lounges around the ship, with the VCL being our favorite. We do use the lounges for morning coffee...but that is about it. You will have 5 drink vouchers per person to use at any of them...at any time.