Hello Sairam,
to use the maximum-paths option under router bgp you have defined two eBGP sessions one for each serial link.
Using a single eBGP session the classic solution is to peer using loopbacks and to achieve load balancing in routing recursion to resolve BGP next-hop.
The classic solution can save router resources, specially router memory ( a single copy of BGP paths is stored instead of having two BGP paths for each destination) and on size of CEF tables.
To be honest, the use of the session on the loopback may be even older then the introduction of the maximum-paths command and as I have noted before it uses less resources.
However, as you have noted mutiple solutions exist to achieve eBGP load balancing.
What to use is a matter of choice, however saving a second eBGP session so avoiding to receive two full internet tables that are identical except the BGP next-hop can allow to use a less powerful router.
If the number of routes exchanged is low the use of two eBGP sessions + maximum-paths 2 can be considered
Hope to help
Giuseppe
