Is “Mobile First” really “Desktop Worst”? Oliver Brooks (Creative Director at Metalab) explains his dislike for the unnecessary use of mobile menus in desktop browser views:
Mobile First should not be taken as an opportunity to over-simplify and, by the same token, Desktop First should not be taken as an opportunity to pile on complexity.
Oliver makes some strong points as he critiques some prominent UIs like Google Drive’s. No matter what your thoughts are on the subject, if you work with interface design then you will want to give this a read.