Because they are unaware that point-and-shoot cameras these days do video too.
You could also ask why anybody buys cameras at all considering most cell phones these days take excellent videos.
A while back I bough a couple of older Motorola Moto e cell phones for $15 on eBay and used them as WiFi security cameras.
https://www.cnet.com/how-to/turn-your-old-phone-into-a-home-security-camera/
I see that, though I actually have 2 - under 30.00 security cameras, one was sent by the vendor since the first would not work with a PC as it said it would, but it turns out the second would not do so either, forcing the Chinese vendor to admit their software was only for cell phones/smart phones, which I do not need or want another bill for. Enough phone calls already.