You are comparing different things. CSS is a technology that helps you to give styles to your website. If you have enough knowledge,of course, you can build a responsive design. MaterializeCSS is framework that makes you easy to make a responsive design, because all the css and the other stuff was already made for you to use it.
On my personal opinion I think that MaterializeCSS is a very basic framework (it's good but there is some stuff that must be developed), I would use Bootstrap that is easier to learn and there is more courses about. If you need the materialize theme for your website use materializeBootstrap.
Hope was useful!!