Small employers are empowered to compete for talent with the bigger players. From an accountant's viewpoint, employee leasing frees CPAs from the deadlines of tax filings. The leasing firm is one company and can handle thousands of workers efficiently. I have to do W-2s for 40 clients and worry about printing each batch correctly. Also, it frees me from preparing paychecks and keeping a full-time payroll person for my clients.
Accountants appreciate the fact that they have an alternative to a payroll service.