I want to start using the new drupal 8 codebase, but I was wondering if I can use it in its state now as a simple blog using views.
The real question is: what's the Drupal core lifecycle look like?
First, we have feature thaw. During this time it's really a bad idea to even try to build anything on it. It's likely to be broken, buggy, and so on. (Although now we have extensive test coverage so it's less broken than you'd think.)
Then there's a feature freeze. People with some knowledge, patience and not too important sites -- say, a blog :) -- could start testing. It'd be great if this happened. You need to understand that there is still no guarantee that your data can stay intact from one git pull to the next. (This is where we are now.)
The next step is beta. From beta and on we support upgrades. So while it's not the quality you'd expect from a released product, it's time to begin serious testing. If you start testing when release happened, your problems will take a lot longer to be fixed.