^ Don't know the quality of the generics, but they can be had for $10 or less.
Why to do it would be if a video card or motherboard integrated video doesn't have analog out but for some reason, someone is really desperate to use a monitor with only analog input. I suppose I could see reusing some old monitor as a 2nd/3rd/etc instead of the primary display, where good image quality at high resolution wasn't high priority.
So the initial question was strange. Is there a benefit to doing that? No, unless that's the only way you can get it connected with minimal extra expense. Always use digital instead of analog if that's an option.