I've been horribly poor at two points in my life. One with children, one without. I couldn't claim benefits because I didn't qualify. But my income was insufficient and I suffered. To the point where I've gone hungry and sat in the dark. It sucks.
I had youth and optimism on my side though. I believed it was temporary and would get better. And it did. 
Even so, that time was a dark time in my life and is probably one of the most defining things to have happened to me. And most of us could find ourselves in that place with just a job loss, an accident or divorce. It's why I won't ever judge anyone on benefits - there but for the grace of god.
I accept that the country doesn't have a limited supply of funds. But I find it morally repugnant that people can be sat hungry in the dark, and that police officers and nurses can have their pay frozen while MPs demand a way-above-inflation pay-rises and claim more on expenses for lavish dinners than a benefit recipient gets in a week.
The trouble with the idea that people can live on £53 a week is a form of 'othering'. It's ok for those people to live in that way because they are not like us and their needs are different.
Like many other posters have said, living on that amount is do-able only in the short-term and only with the proviso that the person concerned doesn't have any debt or additional expenses as a result of the situation that has led them to claim benefits in the first place. Very often that isn't the case so they're starting from a deficit straight away. 
How many people end up on benefits because of relationship breakdown meaning they've had to re-equip a new home with all that entails.
How many people end up on benefits because of a job loss and have tried to shore up the rent/mortgage on overdrafts/credit cards in the belief they'll soon have another job and can pay it off so why downsize (especially since downsizing requires moving, which requires even more money)?
What happens with that £53 when the fridge breaks down and both DC need new shoes in the same month?
What happens when you're told your benefits will be sanctioned if you don't attend x, y and z interviews which require you to spend about £20 of that £53 on travel?
What happens if your public library is one of the ones that has been closed and so you can't walk there?