This looks interesting depending on who you are and where you ride. Over the last few years I have noticed more women riding on the roads I ride. Along with that an increase in women who are out there alone on the bike. (Insert gender bias disclaimer here). I feel across the population women on average are a bit more vulnerable than men and might feel more comfortable with a reasonable self defense mechanism on board such as this one. Not to say that men should not use it.
Most of the bad encounters I have are with men in cars or trucks. You would be amazed at the level of anger some have when they need to move 6 inches to the left or slow down for an entire 10 seconds to avoid hitting me. I didn't know there were so many ways to use the "f" bomb and references to my mother in a sentence. For this reason I somewhat consider something to carry other than my frame pump or a squirt of water from my bottle. I have not so far. BTW I'm as courteous as a cyclist could possibly be when I ride on roads. Always as far to the side as the conditions allow, flashing lights, bright colors, hand signals, obeying traffic signs but it does not matter sometimes. Some people see a cyclist and the rage initiates.