Blog writing, or any type of content production around development for that matter, can help anyone be a better developer. There are several reasons for this, however, I will highlight the 3 I believe to be the most important: reinforcement & continued learning, establishing your professional uniqueness, and increasing your confidence over time.
Reinforcement & Continued Learning
Producing development-related content naturally lends itself to self-directed learning. Whether it's writing a review of your experience with a certain technology, or, providing a tutorial on something you've recently learned, you need to do your homework so to speak. When producing content on a development topic the goal should be able to explain it simply, as it's said once you can do this then you understand it well enough.
"If you can't explain it simply, you don't understand it well enough*." -Albert Einstein.
Professional Uniqueness
As a college student in his final semester, this is the reason that is most pertinent to me. It's no secret that I will be competing with other graduates entering the development space. Some may be more qualified than I am and may have gotten real work experience during their studies. Others may in the same boat as me and have a couple of coursework projects on their portfolio sites. Development content production is something that can separate me from my competition. It's a very unique asset to my complete developer profile, and it demonstrates to potential employers that I have passion & the ability to self-direct my learning.
Producing content can also be the budding first step for a junior developer like myself to begin establishing a network. "It's not what you know, it's who you know.". While I don't believe that statement to be 100% true, there is a certain minimum amount of knowledge one must have to perform any job. However, I cannot deny the power of networking, it even helped me to land my first 'good' job in my previous career in Nursing. I had a friend who worked on the Unit that I wanted to work at and she put in a good word with her manager and then I had an interview the following week. During the interview, I demonstrated my competency for the job by passing the interview questions and shortly after that I was offered a job. So as mentioned, there's a minimum amount of knowledge you must have for a job, but networking is crucial and greatly helps with getting your foot in the door.
Increase in Confidence
With any luck after a few posts (or uploads) hopefully one will notice an increase in their self-confidence. The cycle of research, learning, writing, reflecting, and posting can be very satisfying and will hopefully make you realize that you do have something valuable to share. You will start looking for topics you find interesting and apply that cycle to them, all the while you are creating a digital archive of what you've learned, leveling up your professional portfolio, and growing as a developer.