I saw this little laminated card in the DCA SkyClub this morning:

USE YOUR MILES TO
POUR ON THE PREMIUM

Lift your spirits when you visit THE BAR
at Delta Sky Club. As a SkyMiles member
you now have the option to redeem miles
for any premium beverage.

Valid only for guests 21 years and older. All SkyMiles
program rules apply. To review the rules, please visit
Membership Guide & Program Rules. All Delta SkyClub
rules apply. Please drink responsibly.

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I can't find any reference to this promotion in the on-line membership guide. The bartender here tells me that 100 miles buys an $8.00 premium drink. YMMV.