As Malcolm says, you can't currently stay with DC Points at Phuket Beach Club.
You can though stay at the almost adjacent Mai Khao Beach resort for any number of nights using the DC Explorer Collection (sign in required)
This resort is not directly on the beach though and I suspect Malcolm might agree it wouldn't really match Phuket Beach Club for a honeymoon experience.
I have tried to cut & paste the details below, but the formatting is lousy I am afraid.
Phuket, Thailand : Marriott’s Mai Khao Beach
Set in a tropical paradise, where the glistening sands of Mai Khao Beach meet blue seas, our lavish 5-star resort in Thailand introduces you to a realm of indescribable beauty, flawless service and thoughtful touches. Here, you can daydream by spectacular pools, or venture beyond this Phuket, Thailand resort for an exhilarating day of elephant trekking, diving off the Similan Islands or exploring the wild on a safari.
This package includes:
Seasons Dates Cost per Night (Vacation Club Points)
Monday - Thursday Friday - Saturday Sunday
Gold May 20, 2016-June 26, 2016
September 2, 2016-October 9, 2016 725 1,300 1,050
Platinum February 12, 2016 - May 15, 2016
July 1, 2016 - August 28, 2016
October 14, 2016 - December 11, 2016 1,175 2,000 1,600
Platinum Plus February 5, 2016 - February 7, 2016
December 18, 2016 - December 31, 2016