Someone has to do these jobs. But you are correct, it's not really something to be celebrated. However, the world is what it is. These jobs exist, and people do these jobs. Surely the better option is to not pay tax, rather than pay tax, and claim it back via benefits. Not only do you not feel like your getting hand outs, but there is less administration costs for the government, and less of a welfare bill. Sure, the money isn't coming in the same, so it's a zero cost option, well actually less than zero cost due to the lesser administration cost.
The point is though that these people are better off than they were before. People who are working hard to support their families, are being rewarded for this. And surely that's all good. Obviously we all want paid more, but then that is why there are apprenticeships, further education, and just plain hard graft to work your way up.
I did fine when I was working full time on minimum wage. Rents haven't increased by a huge amount around here since then. Food hasn't really gone up too much. Petrol is a bit more expensive mind you. And I got zero from the government by way of benefits, and started paying income tax after £4400 or something. Sure, I didn't have sky TV or flatscreen tv's, or designer clothes, or holidays, but I wasn't hungry, had a car to get to work in and a roof over my head. I didn't expect that, never mind more. I'm quite sure it is a struggle for those working on minimum wage, but I'm equally sure it's still doable. It's not like we have millions of people starving by the roadside...