Dev.to is suffering from the same problem that sites like Hacker Noon and Quora have already accepted as their faith. For the time being, Google is still treating Dev.to with quite generous "authority", so I imagine their organic traffic is through the roof.

But this has consequences of having your site infested with spammers, poorly written promotional content, etc. For example, one of the things you can do on Dev.to is publish an article, and then add a Canonical link to the original article (your website), which is what a lot of people do.

Having said that, you can find some great articles on the site from people who simply use Dev.to as their preferred blogging platform of choice. Though, even at a glance, the ratio of good and poorly written articles is probably around 25/75 which isn't all that great.