Thanks so much Brerr will have a go later on today, but is it worth it?
Outside of postage are there any other huge benefits.

You can change your handling time in bulk through business policies. If you have an emergency where you'll be away a day or two but want to leave your listings running it's handy to be able to do it in bulk.

When postage changes you can change your policies rather than changing every listing. For example, when letters go up you only have to change the relevant policies and not the parcel policies.

You can still do calculated postage and you can also over-ride your policies on individual listings if you need to.

If you decide to change your payment methods (add bank deposit or remove it) it's easier to do it through your payment policy than editing the listings.