It's true that in the demo video, it's only called out that a third party dependency was removed from the client bundle. And it's true that these types of "infra" dependencies don't make up a large % of your codebase to begin with.
But there's another angle to consider. In thick client apps, product code (everything else) tends to take up the majority of the size of the client bundle. There's a real opportunity here to move some of that into Server Components which would help reduce that footprint significantly. For example consider the case of deeply wrapped components that ultimately render to a single <div>. Server Components could help remove that abstraction tax.
But there's another angle to consider. In thick client apps, product code (everything else) tends to take up the majority of the size of the client bundle. There's a real opportunity here to move some of that into Server Components which would help reduce that footprint significantly. For example consider the case of deeply wrapped components that ultimately render to a single <div>. Server Components could help remove that abstraction tax.