Decent ones can be had for $100, some even less. IMO its a small upfront investment that can save big in the event of a somewhat questionable accident. A lot less stress if you have all the evidence right there.
I've seen a few people at work start to get them as well, so they're catching on a bit.
I use it more for Deterrent and for Parking Incidents.
The last 20 years of driving I've been hit twice and never a problem the police and insurance siding with me. Of course I would prefer not to be involved in it even with my BlackVue.
I got the 650S 2CH. I really didn't want to spend $600 CAN but I'm so flipping anal about brand and design. I also have the 650 1CH on my Murano.