Triple chain V+V+H or H+H+V antennas?

Can anybody explain what purpose these triple chain antennas would make?

A CPE typically is either H or V polarized or H+V duo chain. In other words, one of the chains in the triple chain antenna setup is not going to be used?

RF-Elements are selling these now as ‘Carrier’ grade antennas. But I don’t see the advantage compared to their very good duo chain models. The triple chain sectors are more expensive, so why would someone spend the extra dollar for no reason?

You may get a minimal improvement in receive direction. Not worth the money/space.

"ste; Yes, antenna diversity on the receive end of the AP. But that’s hardly any benefit.

But still, Interline made duo HH and VV polarized sectors, now RF elements these HHV or VVH?
You would think some brains have been working on the design department… why did they make these?

Some suppliers even took these in stock, expecting some sales… is there something we don’t know?