My friend is 38 and disabled following a series of strokes (her first when she was in her 20's and was beaten by her XH).
She can't walk unaided, has lost the use of one arm, is in constant pain so bad that she didn't even realise that she had broken her ankle following a fall. The pain has become normal to her. She's lost most of the sight from one eye. On a good day she can perhaps shuffle slowly from one side of the room to the other, but she is officially recognised as being wheelchair bound.
She has a mobility scooter which she had to buy herself on a credit card, because although she had her most serious stroke back in 2007 she was only assessed this year for a motorised wheelchair and they are still trying to decide if she is entitled to a funded one. They are debating whether a motorised wheelchair (different to a mobility scooter) would make a significant enough difference to her life. Funding is tight, so there's a lot of demand and being approved is almost like winning the lottery.
Outside of the house the mobility scooter has made a big difference to her life. She obviously can't use it in the house and because her house is only accessible by lots of steps, she has to rely on her DH to get it in and out of the house for her.
Even supposing he did get the mobility scooter out of the house, to get to the bus stop at the bottom of their road (maybe 50 yards from her front door) she would have to drive it over a mile and double back on herself on the next street, because of the steps leading down to it at her end of the street and no slope for her to drive down.
Which would all be pointless because she wouldn't be able to drive it onto the bus once she got to the bus stop and she wouldn't be able to get off it, fold it, carry it on, store it and then drag it back off and set it all up again when she reached town.
She lives 8 miles from the nearest town and would have to drive the scooter down 60MPH country lanes, one of which is notorious for RTA fatalities, down roads with speed bumps, over two level crossings and as she got closer to town over a massive road and bridge that has four lanes in both directions.
They do get benefits, including a mobility car, but the money doesn't go far and with several medical appointments a week they use a lot of petrol etc.
Her DH is her main, full time carer and he has problems of his own that make it hard for him to work.
If a bit of free parking means they are able to get into town a bit more often and she can have a bit of independence by then being able to drive herself around a couple of shops alone, after three and a half years of being at first bed-bound in hospital, then at home but too ill to go out, then able to go out only if someone could push her in her wheelchair, then I think it's worth it and I don't begrudge having to pay to park in the same car park that they have parked in for free when we meet up.