Since 2010 disability benefits have become increasingly all-or-nothing. The Tories say "we will support the most disabled ". This is true - it is like a token group they can point at and say "look, we're so civilised, we help these poor people!". But everyone else who is marginally less disabled can go to hell.
I currently qualify for quite a lot in disability benefits. I can't get any mental health treatment, btw, despite asking for years (my actual issues are to do with depression and trauma type stuff, but they think I am a nasty piece of work who's too far gone to bother to help. I think their low judgement of me actually helps with the benefit side though - they may think I am too dangerous (!?!) to be in the workplace).
Anyway, I am able to save quite easily whilst on this money - although to be fair I don't drive/run a car or have a large rent shortfall like many do. My disability also doesn't cost much - I used to pay for private therapy (£40/week). But if I was this disabled by a physical disability I'd barely have enough to make ends meet (buying equipment, paying for care etc).
Also, when I am deemed to be marginally less disabled I will suddenly lose LOADS of money. The next "step down" in benefits is huge. Not only would I lose one particular benefit (PIP) but that would have a knock-on effect on ESA rates (which would drop dramatically) and the worst would be Housing Benefit - I'd suddenly be expected to houseshare rather than have my own flat.
So since the Tories got involved, there is the odd situation like mine where the person doesn't need quite so much money. On the other side of the equation are thousands of people who are now suffering unable to make ends meet.