Temporary Visas can sometimes be cancelled. Or, before the original visa has expired a visa holder may apply for a substantive visa. Those visas may not have the same job privileges as the employee's original visa. Unless the visa status is routinely reviewed, employers won't pick up on these issues. So, they may ask for a VEVO check before hiring.
An appropriate example of this can be when a holder of a Working Holiday Visa applies for a Student Visa. A Working holiday visa has the full-time work permit, whereas a student visa may allow only 40 hours of work a fortnight. Unless employers check the visa status regularly, they may face fines and other penalties.