What a bunch of miseries you really are. How on earth do you cope at Christmas if you can't stand bad weather? Perhaps you should campaign to have it banned?
I live in one of the rainiest parts of England. It rains all summer as well as all winter. TBH there's often not a huge amount of difference between October, February and August.
By meaningful what I mean is that in 2 weeks you can properly wind down, go away (it's almost impossible to go abroad in 1 week where it's possible in 2), do some preparation for the next half-term, visit people etc in a way that's very difficult in 1. You barely feel the benefit of 1 week but 2 weeks is a proper holiday. It's like how you feel after the Easter holiday.
word, I think I've already addressed the point about childcare.
As a parent I would be much less concerned about leaving my kids for 2 weeks in a playscheme or with a childminder or grandparent or anyone than I would be for 6. I would be extremely uncomfortable about them being anywhere apart from school for that length of time. And I'm pretty sure that they would be to. I know that many parents feel the same way. And I know their kids do too.
And unsupervised kids get into a hell of a lot more trouble in 6 weeks than in 2.
I've already said that my own kids get fidgetty after 6 weeks. They're ready to go back to school. Except they're not because they've got so far out of the routine.