Originally Posted by RichardMEL
I also think the big incentive is for the host carrier to provide the perks - for example, UA Premiers get 25% mileage bonus, Y+ seating and 500 miler e-upgrades. I think TG gives an upgrade voucher, etc.
Silver on NZ gives you a free UG voucher and one lounge pass. But it's not that easy to get when flying economy. I too have been upgraded as a S, but only on the carrier on which I had status.