What you are referring to is not a bridge, it is a temporary removable appliance used primarily as a transitional esthetic piece while something more permanent designed to be permanently affixed in the mouth is made. There are many reasons not to do one of these right now and the biggest in my mind is that they partially rest on soft tissue which is really sore area during treatments.

Again I would not worry about esthetics when treatment needs to get done and anything that delays that is not a good thing in my mind. And just to correct the post above since a bridge is cemented on remaining teeth or implants, it does not rest on any soft tissues and would be definitely more tolerable than a removable "flipper" (a derogatory term for the temp appliances because you can "flip" them around in your mouth with your tongue and dislodge them).