Scott, what would be the reason(s) for not using the capacitor and improving the power factor?
The one and only reason I can think of would be an initial upfront reduction in cost to buy the Ballast Kit (costs a little less without the Capacitor included with the Ballast kit).
Maybe the thought of Capacitor failure is another issue???
It wouldn't be such a major problem for a few users to have only one or two NPF type HID fixtures (this wouldn't get the PoCo so mad
), but when many NPF devices are used, the PoCo may respond to the rampant VARs with Penalties to the offending customer (allowing and encouraging the VAR abuse).
The above sillyness is referring to penalties (in the form of $$$ on the power bill), for poor power factor equipment.
On the design side, why would anyone want to setup a lighting system, which runs twice as much in load volt-amps than needed?
Sounds strange to me, but not to someone else.
Wish I had more of a better answer to give, but it appears to be an initial price deal.
Also, if you drive twice as much current through the windings, it may produce more heat and cook the windings more prematurely - resulting in more Ballast replacements / more $$$ income for Fixture/Component manufacturers.
It's the Great Ballast Controversy!!!