I would use them, if you are a new pilot,
Just don't do any HIGH speed descents!
( these can partially, cause VRS ( Vortex Ring State )
Where your phantom will rock side-side, ultimately crashing!
As it passes through its own prop wash !
Happens when you descend straight down too fast )
WHEN DESCENDING, always give some ( forward-backward, side-side )
Motion when descending, to keep it from happening )
Ie: little forward while descending )
They can save your blades, if you ever top over
Or brush against something ( tree ).
( wated to add, VRS, can happen without prop guards !
Not trying to scare you, only make you aware, sorry!
I use them,and I'm a decent pilot, but later if you are
Serious about videography, you might want to remove them
So they will not be present in the video you are trying to
Shoot!
Goes by preference really, but a good idea, if you are a new
Pilot!
Take care, Fly safe!