Which kind of people will pay for extensions like Eightify?

I saw Eightify in Chrome extension store. I tried it and I found it good. But I’m still curious about which kind of person is willing to pay $5 per month, just for video auto summary service on Youtube.

I have no intention of offending or questioning anyone. I just wanna do a simple market research. Probably someday I will develop some cool extension with similiar functions.