Hello Shashank
In general, it is usually best to use a looback interface for all BGP peerings. The benefits of this are shown clearly in the eBGP multihop lesson.
For the scenario shown in the eBGP multihop lesson, static routes between the two routers to achieve routing between the loopbacks are fine. However, there are scenarios where you may want to implement a dynamic routing protocol (in the event that there are additional hops between the eBGP peers) to ensure redundancy and reconvergence in the event of a failure.
I hope this has been helpful!
Laz