There's a reason why there's a such big market for dash cams out there!.
Sure, you can install a mount and record your journeys or time on the road but for how long before your phone runs out of space? Not to mention the field view which can never add match that of a dash cam.
The field view on a phone is limited and doesn't cover a whole lot.
Sure, it can serve your purpose but that totally depends on what your purpose is.
Dash cams are not just to record your road trips or something cool on the road, they are designed solely to record and record over the old footage once your card runs out of space. Not to mention the motion censor detection, the parking mode that enables you to capture anyone trying to scratch or, key your car and post them on social media to shame them for their actions.
There are two channel cameras that provides you with both front and rear view placements to help you avert any false accusations of you being the culprit in an accident, God forbid. Not to mention, they have three channel placements now that also provides you with an in car dash cam view of yourself and acts as a sort of POV.
Like I said, it all comes down to the intents and purposes. I wanted to record for hours and hours so I bought mine and slapped a 256GB SD card on it so it ended up recording the entire journey from Lahore To Galiyat and back, which adds up to a total of 25 hours worth of footage. It's crazy. You can check it out above. Make sure to watch it in 1440p
I hope my response did address your question.
Thanks!
Regards