Back in the day, VFR 121 actually was a thing at certain shops' opspecs, but only for turboprops. You had to work with your dispatcher prior to departure, they had to agree, and the whole thing was a pre-planed exercise. The rules were complicated, and when you boiled it down, it was useful only for a few very specific types of operations. It saved precisely zero amount of time, and there was always a chance when you got to your designation, they'd say "remain clear of the Class B".

It was most certainly not something you pulled out of your back end to try to make happen.