From the rules posted
here, it seems there is no minimum stay/stopover requirement if purchased from SWP
6. MINIMUM STAY
TRAVEL ON THE LAST INTERNATIONAL SECTOR MUST COMMENCE NO EARLIER THAN 10
DAYS AFTER COMMENCEMENT OF THE FIRST INTERNATIONAL SECTOR:
EXCEPTION 1 - FOR TRAVEL ORIGINATING IN EUROPE
TRAVEL ON THE LAST INTERCONTINENTAL SECTOR MUST COMMENCE NO EARLIER THAN
10 DAYS AFTER COMMENCEMENT OF THE FIRST INTERCONTINENTAL SECTOR
EXCEPTION 2 - FOR TRAVEL ORIGINATING SOUTH WEST PACIFIC/HONG KONG/JAPAN
FIRST AND BUSINESS CLASS - NONE
So if no minimum length and minimum stopover requirement this is an advantage over eg *A RTW and may be useful alternative to point to point fare to NA or EU in business/first.