I’ve been obsessively playing with raster graphics tool for drawing and design, and recently with vector tools for the same purpose (obviously free software tools). I produce faster work using vectors for several reasons:
I find vector drawing tools very useful for geometry-based and minimalistic designs, infographics and posters. You can work with large resolutions with low memory, prototyping is easy and painless, and minimalistic designs never get old.
Raster tools have their place for more detailed, painterly work. Being able to easily mix colors, work with brushes conforms to the way painting works. But obviously, both systems can work very well together. Krita supports vector graphics, you work with them as vector but they get converted to pixels during export.
Again, I advocate for free software, specially when high quality tools are available for free. I’m no professional, but amazing work can be produced for a very low cost.