Why not just use Dynamic Topology?

Do you have a time stamp to see what you are referring to? But in any case, there is not just one approach when it comes to Blender and 3D, there is not just one path or one unique way to achieve your goal, you could use remesh or Dyntopo or snake hook or whatever other tool you think is right for the situation, most of the time is a matter of preference or what you feel comfortable with. What you see on the video is a guide more than a rule, as you get more confidence you'll approach things your way more and more, so it's great you pose the question.

Yeah, the Snake Hook Brush is one that is almost begging for Dynamic Topology.

But you can easily switch between Remeshing and DynTopo.

You'll find what works best for you over time, like Omar already mentioned.

Admittedly, I rarely use this remeshing approach when I sculpt. But I wanted to demonstrate how it could be used though, maybe not an ideal case here.

Typically I stick with dynamic topology.