
The downside to consumers is that the gift certificates must be kept around for that special time you wish to use it. I've got a Le Fou Frog gift certificate gathering dust right now because I haven't made the time to use it yet.
There is also a downside to the restaurants as well. I spoke to one owner about the deals and he admits that they probably lose money on the deals, but they hope that it leads to new customers. The worst situation is when they see a regular customer using one of the coupons. Owners also sometimes get burned when users only tip on the final bill amount disregarding the coupon's inclusion.
My personal take is that these deals are great for the consumer, so-so for the restaurants, and ultimately will lose their appeal. Restaurants don't mind doing one of these deals a year. However, since these deals are sent out on a daily basis, you have to sift through the crap to find the good deals (Every other day features some sort of spa or hair salon... my "fro" doesn't need that shit).
Once folks have a chance to try out a few new places, all but the hard-core savers will begin to lose interest. Until then, suit up and coupon up!