New Software A/P package- "voucher less "system, what is?

HI We are looking at some new Iseries based ERP pacakges. Right now the
major ones. All of them talk about being a 'voucherless' system.
Currently, we are a voucher based system.

One of the Accounting folks, was interested in going to a voucherless.
Another asked, what is the difference one way or the other. I was asked
how is this done in other places. I have no good idea, as I was
unfortunately out of I.T. Programming during the difficult economic years,
2003-2005. So I don't remember systems that well.

Perhaps someone on the list is more actively involved in accounting
systems, and can explain the benefits of a voucherless system?

Thanks,
Steve