I think Pluto and VSCode are both valuable tools for a beginner in Julia.
In Pluto, you can focus more on the interactivity with the code, where you can produce notebooks filled with equations and code that solves those equations. Add a few sliders and you can quickly gain further insight on your problem by changing certain parameters.
On the other hand, you would use VSCode to produce more “serious” code. What I mean by that is that, while Pluto is great for short demonstrations, you do not really want to use that to create a module with functions. In VSCode you can divide your functions into different files and have a really nice workflow for developing modules if you use Revise.jl.
So the choice just depends on what you want to do. In my opinion, learning both is beneficial and you just stick to the one that fits your current task. Also, take into account that Pluto uses his own package manager, which means that every time you load a Pluto Notebook it has to download and import the packages. This behaviour can be modified to instead load a local environment so you do not have to run this lengthy process everytime.