I can understand the frustration with inset days a little. I look after my dcs on my own and got asked by work to swap my regular day off so a colleague could take leave that day. No worries.
That evening, an inset day gets announced for the day I've just promised to work. A month's notice. No holiday club. No family anywhere near. Bloody nightmare to cover.
If inset days were all in one block, co ordinated with other local schools or tagged on to a regular holiday, in my humble opinion it would all be infinitely easier to manage for parents and childcare providers.
That's all.