For character design specifically, no. In all honesty while I did sign up for a perspective course at the same time as taking dynamic sketching (the course this one is based on), I ended up dropping it due to being too overloaded and having to decide on what would ultimately be the better fit for me. I didn't end up going back to take it later, despite working as a concept artist with a focus on both environment, prop, and vehicle design.

In my experience due to the scale of the forms and objects character design involves, having strong spatial reasoning skills (even without the very specific techniques and understanding a proper linear perspective course would impart) should be sufficient.

Drawabox is more tailored to 3d spatial reasoning than dynamic sketching (we drop a lot of other cool stuff that DS covers to maintain that focus), so that would arguably put you in a better position than I was in, as far as the perspective question is concern.

Linear perspective is still useful to learn, but I think a lot of people go into it way further than is strictly required, simply because of the assumption that illustrations are done all working off complex perspective grids, plotting everything back. This is really only the case if your particular illustration requires perfect perspective - which is very rare. Of course there is also the additional benefits of those perspective courses having additional impact on your spatial reasoning skills, so I'm not at all discounting their usefulness - but most of the "loose" and "general" understanding of perspective you'd use in your day to day is indeed covered here.

I would probably still recommend those focusing on environment design and illustration to take a perspective course (even though I myself didn't - I'm also a fairly mediocre illustrator) but when it comes down to a specific focus on character design, I don't think it will actually make too much of a difference over what we explore and develop here.

Better you look at analytical figure drawing courses, which will go further into how you can take the spatial reasoning you develop here and actually apply it to constructing complex human bodies. Also, studying form language and other design focused topics would be a good place to focus your limited time as well.