[TowerTalk] Ground radials for phased arrays

[n0tt1 at juno.com]

Gents,

About on-the-ground radials for vertical phased arrays...some
"instructions"
have said to connect the ends of the radials to a "buss" that (more or
less) 
divides the 4 elements in say, a 7mhz 4-square.

My question is why do that....Is it just to save on radial wire
or is there a technical reason for connecting them to a buss?

Thanks,
Charlie, N0TT