Christ alive, @Wildflowers99 you really don't know what you're talking about.
UC does not fully cover most rents, there is a LHA that is capped and means that from your personal allowance which is meant to cover bills and food you have to cover the shortfall. Real life example - my LHA is 695. My rent is 850. My personal allowance is 393.45. Do the maths. I am "too broken to work" which I hope to remedy, and do get that component too. My Utilities are in the region of 250 a month, and I have other commitments that see me struggle every month.
I manage, but only just. My life is small, devoid of socialisation, and constricted by caring responsibilities. This too will pass. I'm lucky that I am in relatively good physical health for my age, but I am trapped by other circumstances beyond my control.
For someone with a disability, they would, even in my one bed flat, be paying 250 a month or more for heating alone. I hardly used it over the Winter, because my health allows that.
You do not get to judge what constitutes a miserable life, nor compare apples with oranges by simpering about third world countries. 400 extra, if you have 400 or more expenses associated with your health / disability can be the difference between a life worth living or not for some people.
COL is also variable according to area, while benefits are largely fixed. And a glib "well move then" will be met with a long list of reasons why that's often detrimental to the disabled.
Finally, you are fixed on the idea that medical care is easily accessed in a timely fashion and is free. If you can't access that free healthcare, or you have to wait and deteriorate it's pointless to harp on about it.