A get a bit anxious having to monitor both my DJI video link and ELRS link when flying around trees and things. I’m thinking of selling my Radiomaster and switching to the DJI controller which will share the FPV link.
Is there any disadvantage to doing this for a novice?
the wiring is easier if you use the Air unit as the receiver as well.
But the penetration power on ELRS or Crossfire will be better than the DJI Air unit. Not that it makes a difference because if you lose video then the result is most likely a crash anyway so still having a strong radio link will be the least of your worries lol
Unless you have GPS rescue configured, and are quick enough to enable it 
Thats true 
Definitely an advantage of having separate link and video
Golden rule is:
RC link must always be longer range than video range
If you lose video you still need to be able to control it
Even if it is just to switch RTH or ‘kill’ it for safety
What if my failsafe set to kick in when link is lost?
At the moment my stage 1 failsafe is to go into angle mode, centre the right stick, and set throttle to rise slowly (back into RF range). Then stage two is GPS rescue.
I’ve only used the air unit for video and control once.
03 air unit and the penetration was poor.
I imagined that by using it for both it reduces the range.
Now have the same drone on crossfire and it’s much better.
Using the Air Unit as receiver reduced your video link?
I felt like it did. Certainly feels better now and range has improved.