Thanks for your reply Dennis.I checked that JS Bin code. "In the former case, the value of the control will change when the value in the model change." , and vice versa won't be true , right?? that is (if value is changed in control by user , it wont change it on model)?
If the above is true and suppose if the scenario is I bring the data from json file to model , then (its unlikely that the source data in the model is going to change during the time user is viewing the webpage) , would'nt it be better from performance perspective to use SetValue instead of binding?? Saw your reply on performannce after this post so editing 
Kindly suggest me on this as in the JS Bin code , i am able to get the same functionality for "static" field too using setValue hence I am still unable to get a scenario where binding wins over setValue.
Thanks
Amber