I would think there are few things here.
1) The government don't want people smoking at all owing to the increased healthcare costs (even taking into account additional duty on cigarettes, probably, I have no idea)
2) Consideration needs to be given as to whether concessions on smoking encourages any non-smokers to start smoking
3) As a non-smoker, it's always been the case that the smokers rule where everyone sits (even now, I am occassionally forced to sit out in the freezing cold to accommodate smokers) so, practically, I'd be stuck in the smoking room even though I didn't want to be there.