The idea of a blogging platform that supports ActivityPub is a great one, but WriteFreely is unfortunately missing a lot of essential fediverse features at the moment.
I'd like to be able to interact with other users and I'd like to have more control over how posts are published. For example I would prefer it if there was an option to share blogposts as links instead of dumping the full text on the fediverse. Also WriteFreely does not have the capability to set your profile information like a description or avatar, it is very limited.
I will continue to use WriteFreely for this blog, I absolutely love it as a writing tool, but I will turn the federation features off for now. Instead I will now be hosting my own single-user Pleroma instance for Jiyu. This allows me to publish blogposts and other things in the way that I want and also interact with them better. I think this is the better option since it also allows me share small updates that do not require a full blogpost.