I've noticed a benefit to writing regular blog entries.
At every level of education, whenever you get a writing assignment, it is to write a certain number of pages. Thus, you end up planning ahead of time how long each part of the essay or paper will be. If it's too long or short, you add "filler" or cut things out accordingly. You follow the assigned structure, regardless of how the ideas should really be expressed best.
When writing blog entries, because the initiative is yours, you have none of those issues. There is no page requirement, so you can write every idea using exactly the number of words it takes to express it. If an idea isn't coming out right, or doesn't fit with the rest of what you wrote, you can cut it out and save it for later, or delete it entirely. If your train of thought takes you in a new and more complicated direction, there is time and space to develop that too.
Eventually you find that your thoughts and logical processes are displayed, almost graphically, on the page. If there is a weak point in your argument, it finds expression in a weak sentence. You can't fix the sentence without fixing the argument too. But once every paragraph division makes sense and every line flows smoothly into the next, you know that the argument you have just written is flawless and is guaranteed to be correct.