I do it all the time, not nobbish at all. I view it the same as driving past all those queuing at a petrol station to get a pump the same side as their filler cap
No, quite different. That’s making using of unused capacity. If everyone did it, the queues would be shorter.
Doing a circuit of the roundabout is just queue jumping. As you complete your 360, you prevent someone who was in front of you from entering the roundabout, and you’ve also used up more of the junction’s capacity by being on it for longer. If everyone did it, queues on all approaches would be longer.