This wasn't a crime before?
As I understand it, an employer not paying your wages is (was?) treated as someone not paying an invoice. Like if you don't pay your power bill, you owe the power company money and your power company has a range of options to get the money from you but it's not a crime to not pay your power bill, even if you never intended to pay.
I think this Act recognises that there's quite a difference between not paying an invoice when you are a private individual vs a company who is responsible for many people's livelihoods.