Front-end/Web design has evolved into a discipline of its own.
If you come from a different field, say programming, I can see how CSS looks like a bad solution to an already solved problem. So you're incentive is to stick to what you know and use tables for everything.
However, there's much more to front-end design that just having text and images show up where you want: user-agent targeting, SEO, accessibility, typography, graphic design, etc... There's a lot to learn, and CSS is just a small part of it.
If you come from a different field, say programming, I can see how CSS looks like a bad solution to an already solved problem. So you're incentive is to stick to what you know and use tables for everything.
However, there's much more to front-end design that just having text and images show up where you want: user-agent targeting, SEO, accessibility, typography, graphic design, etc... There's a lot to learn, and CSS is just a small part of it.