Based on my experience with Accor Traveler Membership, The membership is great, if someone is a hard core foodie.
From a Restaurant standpoint, I got 14 Vouchers (Complementary Dine in for 2 in each voucher, implies 28 Complementary buffets). The only drawback is this vouchers are all spread across cities. Since I used a South Indian Address, My vouchers were spread across Bengaluru, Mysuru, Kochi and Chennai. The extra Vouchers for stay, Birthday Cake, Dessert, Drinks are additional perks. If I could use all this Buffet vouchers (Of course, if i travel), this this is a great value proposition.
You unfortunately will have to check-in for anyone else to use the points.
Membership might give you better rates while booking hotel rooms, especially the red hot rates. I wont recommend using online points while booking. They are costly in comparison. What i have done so far is I give my card details and book the rooms with best available price using the membership. And When I check-in, I inform that i will be redeeming points. Another Advantage of a membership would be the welcome drink, which is cool as well. They will give you a voucher while check-in, which you can use anytime on the day of check-in
Hotels will show options to Pre-Pay in advance, though is mostly 20% more costly. If Prepayment is the plan, then the membership does not help. Its the same price point.