How useful dev.to is for the beginner?

For me, this depends on where you are on the "beginner" spectrum.

Have you been coding for 1-2 years and am know how to hack some basics things together in a language or two, but am unsure how to polish these skills enough for a real job? Dev.to will be great to you if you invest in reading different posts, and writing a few of your own about how you're learning.

Are you just jumping in without ANY real knowledge of a programming language or the environment? Dev.to will likely still be useful to you as long as you focus more on the beginners or "explain it like I'm five" sections. But I'd recommend doing something like codecademy to practice a language or two, and reading Michael Hartl's "Learn Enough to be Dangerous" books along with the Rails tutorial. Those are all good ways to start building a foundation if you're completely self-taught, and there's likely many others other devs here will be happy to share.

If you're absolutely new, there's also six really important steps you can take here:

1. Get a specific idea of what you want to learn
2. Be enthusiastic about learning it
3. Ask!
4. Thank everyone who answers
5. Share your progress as you learn
6. Help others who also ask once you're far enough along to have some answers of your own

I think there's a lot of useful posts for beginners on every stage of their knowledge—from articles which teach you programming from scratch, to ones which point out what mistakes you should avoid to be a better dev. Also, everyone here seems to be very kind and helpful.
So it's great to be a part of this awesome community!