I think it doesn't benefit employees.
We saw that same kind of manoeuvre when Mike Harris came to power in Ontario. There was this attempt to flexibilize the rules, or change the rules under the guise of flexibility, in a way that meant it undercut and circumvented those entitlements altogether.
With respect to employers and just-in-time workers, I think there may be a false economy. I agree with you that employers want to hire employees on a just-in-time basis as disposable inputs into production, but I think one of the consequences is that you don't see the business strategies that rely on investment in machinery, equipment, productivity-enhancing innovations in the workplace, because they can't compete on the basis of low wages and the “precaratization” of labour.
There is an economic advantage to closing off the low road of competition and requiring employers to adopt business strategies that don't rest on the super-exploitation—