It is not a bridge camera, but I've used a compact camera (Panasonic LX-10) a few times as the b-camera.
In pre-covid times, a small theater group had me record video of the production. I would record the whole show as one long video (1.5 hours). In post, I would break the video into smaller scenes and export them to youtube. At the time, my A-camera of choice was the Panasonic G85 since it has no limits on recording. I recorded FHD (1080p) as a matter of habit (my other video gig involved shooting 10-12 hours, and 4K was just too much data).
Now, since Covid, the group has been limping along, but so far they haven't needed me to record their shows. I've given the G85 away, and if I did video now, I would use the OM-1 which also does not have a video record limit.
Where I used the LX-10 is I would put the camera on a tripod across the room to get a backup, and potentially record from a second angle. I would use the phone app to control the LX-10 remotely. Because it is a fixed lens camera, I can zoom the lens from within the phone app. With the exception of 4 older, slower lenses, none of the micro 4/3rds lenses can be zoomed from within the OM/Olympus/Panasonic phone apps.
I also have a cheap wifi controlled pan/tilt head to adjust where the camera records. The pan/tilt head is more made for phones, and it has a weight limit that prevents using it with the heavier cameras. But the LX-10 is light enough that I can use it easily.
This is primarily as a backup in case something happens to the main camera. In the fact the one time I needed the backup (my G85 once lost first 13 minutes of sound due to microphone cable not plugged in correctly, before I plugged it in correctly), I hadn't started the LX-10 in time so I could use the audio from the LX-10.
Now, I don't do any video editing other than breaking the video into smaller segments and putting a copyright marker on the first seconds of the video, so I haven't used it for the second angle of the shots. But if I did, I could certainly take advantage of it.
The LX-10 does have 3 drawbacks:
1) The battery only lasts for about an hour. You can (or at least could in the past) get a dummy battery that provides unlimited power from a 5v USB wall wort or power bank. The last time I used the LX-10 to record video, I recorded a 1.5 hour video using the dummy battery.
2) The LX-10 can record unlimited FHD video, but only about 10 minutes of 4K video.
3) The LX-10 does not support an external microphone port.