Yes, there are currently exemptions to travel bans. But I'd assumed that "zero covid closed borders" would involve more than that. Surely now no one (or pretty much no one) is travelling for a non-essential reason. Everyone (caveat: there may be the odd tourist, but their numbers I assume are negligible...) trapped by the hotel quarantine requirements will have a justifiable reason for travelling. Visiting ill or dying relatives or attending funerals abroad. Working abroad. Accessing medical care abroad (actually, they may not have to quarantine on return, but not sure if that's been confirmed yet or not) . Supporting vulnerable people, travelling to access education and so on. But I understand that they will still need to quarantine - even offshore workers may not be exempt according to reports this morning... I'd have thought they'd have clarified that before now, but hey.
So it's not ridiculous to suggest that in the hypothetical closed border Scotland there would be similarly few exemptions. Or rather, they would be allowed to travel but end up having to pay thousands in quarantine, putting it out of reach of anyone but the wealthiest.
It probably is hyperbole suggesting it will be "forever". But someone said the other day their industry was projecting 2027 for return to full normality/ productivity. Which may as well be forever for someone with elderly relatives abroad, or children not able to see parents or whatever.
I'm not saying it's impossible or an awful idea (though I'm veering to the latter frankly) but there are many many awful consequences that I don't think have been fully factored into the elimination strategy as far as I've seen. I understand the "well, we're not being allowed anything at the moment anyway, and spreading the virus will just make everything worse so we may as well take away some people's rights to see their family to make things better for the rest" argument. But I don't think it's a particularly fair argument and some people will suffer much worse than others.