Why a deeper depth of field?
Because this is a type of photographic portraiture called neorealism, or hyperrealism. It shows him down to the pore level, the whisker level, in unflinching, direct eye contact with the camera. But, instead of the man, the person, the personage being sharply shown, it's a shot that focuses on his eyeglasses. The shot has lost a tremendous amount of impact because the depth of field is so shallow, Instead of the portrait truly featuring or emphasizing _him_, it shows us that you made an unwise f/stop choice; it shows off YOU, not the subject. And in this kind of work, everything within the final shot is _a choice_. This type of portraiture is designed to emphasize REAL-ness of the subject, but the execution of the shot is marred by a shallow depth of field that screams, "Look! I shot this almost wide-open! Look what I can do with a camera!"
I don't want the above description to sound too harsh, but...Me, and 15 other photography students had the above discussion 35 years ago in a fine arts photography class critique that featured hyperrealism as a topic, and I've heard far, far worse ways of describing what your picture is like. You asked ,"Why?" and I gave you an unvarnished explanation of the issue with shooting with ultra-shallow depth of field on a "type of photographic portrait" that almost demands deep DOF for maximum impact.
The shallow DOF kills the "impact" of the hyper-realistic goal of this kind of shot. Choosing to shoot this as a shallow DOF shot was not the best choice to further a neo-realistic or hyper-realistic artistic endeavor. This is a matter of taste and discernment.