Oh goodness, I LOVE love CSP. I had looked at so many other applications and found that CSP made the most sense. Some months ago, maybe even back in 2020, it received a comic-geared update that makes creating webtoons hassle-free as it's going to get. It can also accept abr. Photoshop brushes now, too. Everything about CSP makes creation a lot easier, and the interface is more customizable than I've seen in any other engine.
It did take me awhile to get used to CSP. I was switching from Procreate and Photoshop, and I even almost dropped it . I'm glad I stuck with it. Everyone has their own software preferences, though
As another user said, CSP is not a requirement. You don't have to use it. It just makes some things easier. Some people even create comics with Procreate, which although is great for drafting and illustration, is a bit of a limited hassle when it comes to multiple pages, longer shots, etc, which Paint Tool Sai would do much better with. If comics can be created on Procreate, then Paint Tool Sai will do as well.
It is not the tools that make the artist. The tools just help your flow. ^^