I have to disagree. I don't think you have to necessarily be doing figure drawing- but referencing while making the comics even if its from a 3D model can assist them in learning. I do it all the time because there are poses I still need to learn how to do. People can start a comic at whatever point in their art journey, more power to them.
I do acknowledge that the title of this topic is a bit misleading (it was moreso just supposed to be my opinion, I didn't mean it to come of as YOU CAN NEVER DO THIS! I might change the title because I don't want it to come off that way)
There is no 'only' way to do something. I understand if someone needs an artwork but has to do it themselves because they can't afford an artist. That's a different situation to someone making a full on comic. In your case, I think you've done an excellent job with your cover.
But I think that if a comic artist is solely relying on 3D models for their poses because they 'can't learn it' they should change their mindset. They have the capacity to learn it, but it doesn't come quickly. Art is not easy. I understand that. I've had horrendous anatomy before which I've had to learn to improve over the years.
But, if someone wants to make their comic through tracing models, that's fine. I was moreso discussing this 'trace over 3D models' advice for people who are looking to improve drawing bodies and are new to art.
If you're making a comic, you need to know how to draw people. It's fine if you're still learning, but relying on tracing models likely will not help you learn to draw your own proportions in your style if that's what you're going for (it depends on your goals as you mentioned) It can become a crutch, especially when you don't feel confident drawing bodies on your own.
A lot of artists will tell you to practice to improve, and that is how it goes for the most part. Just like any skill, dedicating a lot of time and effort to it is necessary if you're looking to improve. Learning and improvement is different for everyone, but that doesn't mean someone is incapable or untalented to do it.