Good thread. I've mainly used GoPros as my dashcams to date. The pros are the wide field of vision which basically captures everything out your entire windshield, from left to right and top to bottom; and the ease/simplicity of use. Just put it on the mount, set the tilt, get the screw good and tight, press record and forget it. No framing/panning required.
Cons: The wide field of vision and lack of zoom means that even things relatively close appear far away. Even with the newer 4K models (Hero 10 Black I got in 2022 and Hero 12 Black later last year-haven't used that one for chasing yet) you can only blow the picture up so much before the quality starts to noticeably suffer. Second, these things (going back to the Hero 3 White I got in 2013) suck battery power like there's no tomorrow. If you start them recording and "forget" (as above) for too long, it's easy to run them out of juice or fill up the SD card.
First and second attachments are example frame grabs from the dash-mounted Hero 10 footage of the Ottumwa/Martinsburg, IA (before the closer Keota EF4 developed) and Plato Center/S. Elgin, IL tornadoes from March 31 and July 12 of last year.
Ever since I got a newer camcorder with 4K capability (Canon VIXIA HF G60) in 2020, the VIXIA HF G10 I bought off
@Dan Robinson in 2013 has been stored in the G60's box in my closet. I've occasionally mulled over repurposing it as a dashcam for chasing, but that would run into the issues he mentioned in the post above and its own low-light performance is not stellar, as evidenced by the fact that I had to put it in its slow-shutter "night vision" mode for the Hanna City, IL tornado in March, 2016. The frame captures are decent enough, if a bit grainy (third attachment), but the video itself looks like choppy security-camera footage (as a YouTube critic pointed out when I re-uploaded it for the 8th anniversary earlier this month).