I prefer the premium cabins to have empty seats, it means you get a more individual service. Meanwhile if you want to fly in J or F, you can always pay for a ticket.

The trouble with airlines that fill their premium cabins with people who aren’t paying for a revenue ticket in those classes, they devalue their product and what’s more it makes people less likely to purchase a premium ticket on the hope that they get a cheap upgrade- BA already get that a little bit with AUP for exampleC which is why they started the restrictions on individuals who they think use this practice to ‘encourage’ such individuals to purchase the class of ticket in the cabin they wish to fly.