There are scenarios when outside of a view we need to fetch results of any particular view. This is a very specific case when we just want the records compiled by Drupal Views. In that case obviously views api or views hooks are of no use, as we are not looking for event driven activities. It’s just the results needs to be fetched using views because of the complexity of the criterion on which these results are computed.
We won’t go for this approach when we want simple results like all the nodes of a specific content type sorted alphabetically. In that case, simply db_select would be better choice again depending on various project specific factors. In general, we can’t actually tag any approach as the best or optimal for general purpose as these are scenario specifics.