Any premises-office, residence public or private, must have signs in place for general information, direction or exigency. There is no compromise on the last one as NBC has clearly mandated that photoluminescent signs are to be installed for escape route direction.
But there are many other seemingly ordinary signs which may be fancy or aesthetically pleasing but of zero use in an emergency situation. For example, doors have push or pull signs near the handle. In case of a fire or smoke situation a sign that does not glow will be useless. A photoluminescent sign will help the runner to do the right thing and open the door swiftly and escape. Similarly, signs that identify a room need to be photoluminescent only, for example SERVER ROOM, MEETING ROOM signs will glow in the dark in a fire or smoggy atmosphere so the runner will know which room he is heading for. Just as EXIT sign is a photoluminescent one mandatorily, some others may not be mandatory but still necessarily need to be photoluminescent to help people in darkness to manoeuvre quickly and easily within enclosed premises where seconds can be critical.