It was all about not screwing the poor over, and try to get the long term unemployed back into work, which would likely be those that benefit most from these measures (thus making working more attractive).
Another thing was the housing benefit, there are people/families who are claiming thousands of £'s a month in housing benefits particularly in areas of London, which might be bad enough in itself, but those families would have to earn 6 figure salary to stay in the house if their benefits were talking away (i.e. they got a job). If the family earned say £50k i.e. both parents went off to earn national average wage, they couldn't afford to stay there and would have to move.
This is a classic benefit trap, I applaud the national maximum housing benefit. A nice knock on effect will hopefully be cheaper rents all around as the Government induced price floor is removed stopping the "crowding out" for those that are in work who pay rent out of their own pocket.