I received the offer by phone in November; $269 but including $100 on voucher. Mention this only for comparison.
As you note: Dining benefits are only for participating hotels and in "Asia" are very few: one hotel in Singapore, one in Batam but quite a few in China. The agent told me that more hotels in Asia were joining by January 1st but nothing has changed/added. fortunately I told her to ring back after they join.
Am advised that the free night is anywhere and although I haven't tried to book it (as I haven't taken up the membership), I did get 2 free nights from the "Into the nights promotion" and booked the IC Singapore with them so...I suspect "top IHG hotels" are OK but may be subject to availability.
JV
Thank you, Jacques, for your replies. We are going to be in Beijing for 2 days in May, and if joined, might check out dining at IC in the Olympics area. I have read about IC in Amsterdam and Paris, and thought either could be used for the free night.