This video is about stock preparation using various hand planes for specific tasks. While it is the no.4 smoother is versatile but the 5 and 5 1/2 is the most versatile of them all but as your experience grows you begin develop a sense of understanding what plane is better suit to each task and what bevel angle is better suited to tackle reversing grain. So owning the most planes is not the goal here while we all appreciate hand tools and love them to bits and I’m sure none of us would reject owning an array of tools you most definitely don’t need them all. For the sake of speed production owning a few extra smoothers is not a bad idea, when one blade goes blunt you just grab another plane and your back to work.
I hope you gain some level of insight into this procedure as it is a normal integral part of woodworking with hand tools.