If statutory holiday was reduced then the people at the bottom of the pile would be exploited - since there are some overheads to having more employees doing doing the same number of total hours, it's cheaper to have fewer people doing longer hours, so companies will push for it. Those who are skilled (like most Register readers) have flexibility here so can insist on better terms, but the people at the bottom of the pile will get exploited, and that's not a society I want to live in.
There are possibly also other benefits that are harder to measure - ensuring people have some time off will benefit their health and so reduce the drain on the nhs/incapacity benefit in the future.
That said more flexibility is useful. My current company ignores bank holidays- you get an equivalent amount of annual leave, you can take it on the bank holidays or at another time, great for taking time off when it's cheaper to go on holiday. My previous one let you buy or sell up to to a week of leave (although when when I went to buy some they looked at me surprised as they were so used to people being overworked and selling some of their leave)
I disagree with the article, but it's good to be challenged as to why I do, more of this sort of thing.