Bizarre design! As it screws into the regular round bulb socket, and also needs room to revolve around as it enters the socket, it does not result in a space-saving light fixture. The only advantage is less space for storage and transportation, but at what additional manufacturing costs?
There are already a myriad of miniature halogen bulbs and new LED lights that offer much more than this flat bulb. This flat bulb reminds me of the square watermelons offered in the Japanese market; their only advantage is less storage space.
"Old age is the most unexpected of all things that can happen to a man" -- Leo Tolstoy