Entering Bills - Should employees be allowed?

I work at a non-profit relief and development organization that often has to send checks to our international fields. We think the best way to do this is to enter the payment information into the vendor bill screen and then have the check print from the bill.
We'd like to have supervisors approve the bills before they are paid. I know this functionality exists with purchase requests and purchase orders, but we're not actually receiving anything in return.

2 Questions:
1. Is there anything wrong with allowing employees (that are not A/P) to enter bills for this purpose?
2. Is there any way to set up approval routing for bills?