Just because you can doesn't mean you should. 30 years ago, applications were built with long life-spans in mind, so dropping into very low-level code could make financial sense. Today, programs are generally designed for adaptability and compatibility. The target is constantly moving for the vast majority of applications out there. Dropping into assembly rarely makes sense anymore, because the mantra is "good enough" rather than "best" because even the "best" won't stay that way for long.
Of course, different industries will have different mileage. If you do most of your work for embedded devices or industry-niche things like robotics or satellites, then by all means dive into the 1's and 0's.