"snip"

However one of the benefits of impedance
matching for certain antenna types like the inverted-L is you can also
achieve an effective RF ground for the coax shield when the matching
transformer (unun or balun) is located close to the ground. This allows
for a short (effective) ground connection from the common end of the
transformer windings to ground.

That would be a side benefit. The main reason for this grounding
arrangement is that the valley I live in gets wicked lightning storms. I
think that by having the entire antenna operating at DC ground with the
low resistance of the twin RG6 braids entirely outdoors and directly to
earth ground would reduce the possiblity of a direct lightning strike on
or near the antenna conducting enongh current past the grounded balun to
ignite the house where the leadin enters.