I think it's a good idea. The problem with Tumblr is that you're encouraged to theme your blog, e.g. fitness, hunger games or whatever, so you end up having to make different blogs for each topic you're into because people that follow you aren't going to want to see workout logs mixed in with hunger games gifs.

It is a nifty idea to just be able to toss down some random idea on to a blog with no other pressure. With tumblr there is the pressure of having to blog regularly, queue up posts to publish every hour and keep to a theme etc.