If you are purchasing a case but don’t plan on shipping it via commercial carrier (or at all), then specifying surface mount hardware will result in substantial cost savings. While surface mount hardware is functionally similar to recessed hardware, it is more vulnerable to damage.
Having the ability to select surface mount hardware extends the range of options available to you. One of the advantages (besides cost) of using surface mount hardware is that cases can be smaller. For example, in order to install a recessed handle on the side of a rack case, the minimum height needed would be 4″. That’s a 3 rack space (5.25″) minimum height. Using surface mount hardware, this could be reduced to 2 rack spaces (3.5″).