Most often realized benefit of maintaining writeups on projects is using them as my own reference when I forget how I did something :P
Second most often realized benefit is forcing projects to actually get completed. Unless something is clearly a multipart adventure, I try to force myself to actually finish the thing before writing it up. I enjoy writing things up and documenting them, so it's a motivator. I've also decided to put things on my site first, rather than bite-size entertainment-for-others posts on various sites.
As others have said, it definitely has helped with interviews, though I haven't had to do one in a while.
Second most often realized benefit is forcing projects to actually get completed. Unless something is clearly a multipart adventure, I try to force myself to actually finish the thing before writing it up. I enjoy writing things up and documenting them, so it's a motivator. I've also decided to put things on my site first, rather than bite-size entertainment-for-others posts on various sites.
As others have said, it definitely has helped with interviews, though I haven't had to do one in a while.