Small doubts in PI

Hi,

Can anyone please explain

1.What is the need for archiving/ What kind of messages are archived (Will Customer/Client ask us to archive particular message?)

2.I need an example of FILE --> RFC scenario involving Third Party such as SEEBURGER

(PS: I know the technical implementations. I just want to know a Business Scenario)

3.While moving SLD, IR, ID objects from DEV-->QA, QA-->PROD, is it mandatory to use a tool such as CMS/CTS+? (If I'm not mistaken we can do it directly by exporting them and import them in required servers/ By creating groups in SLD and export them. Right?)

Thank You,

KK,