non-valuated GR

Hi Readers,

SAP textbook mentioned that non-valuated can be applied to consumable material.

May I know:

1) can I apply non-valuated GR to procurment of services?

2) can list out the pros and cons of using non-valuated GR?

3) can give some real life business scenerio that uses non-valuated GR?

Thank you, your input is appreciated!