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Yes, the built-in dash cam will record your track sessions. However:
It doesn't include a timestamp on the video, so it's difficult to get a lap time from the recordings - also, no telemetry (speed, track location) is logged, which many people want.
It records in 1 minute clips that you need to piece together after the fact - generally, there's a fraction of a second pause between the clips, see the previous point
it only saves a 1 hour loop by default, overwriting the oldest data after 1 hour (it's recording anytime the car is on)
you can save the previous 10 minutes of video
the previous 2 points mean it doesn't work well for the sessions I have done, which generally consist of 5 sessions that are 15 minutes each
the image quality is generally pretty poor (the exposure settings are all over the place and it has an odd tint to it). It's OK for documenting an accident, but not something you want to show off.
As an alternative, I'd suggest a GoPro, Garmin VIRB, or any of the other purpose-built action/dash cameras or go the cheap route and mount your cell phone to the dash and run software like Harry's Lap Timer on the phone.