Muffin,
Consider the concept of not having to Book In or Book Out for a starter.
Consider the airports remain open 24 hours per day.
Consider the airport lighting is Pilot Controlled after the Control Towers close.
Cost alone will kill aviation but also the lack of access to facilities on a 24 hour basis as well.
Ours is not a perfect system by far.....but it sure by golly beats the UK system hands down. Anyone that argues otherwise is at risk of drowning in a drizzle in my view.