Hi, welcome. You're lucky that you remember so many dreams so vividly. There are only two reasons you might want to keep a dream journal that I can think of.

One is if you don't remember the details of dreams you had a long time ago, and would like to keep track of them. You say you still remember dreams from 10 years ago, but I'm guessing (unless you have some freakish memory) you don't remember all of them, and if you ever want to be able to look back and read about your dreams again, maybe even in the very far future when you're curious and have forgotten what kinds of dreams you had when you were your current age, you might want to keep one.

Another is to look for dream signs or perform statistical analyses. For example, if you want to look for exactly how many times you've dreamed about a certain person you can scan for their name. Or if you want to find out if there's a correlation between the amount of sleep you get and the vividness of your dreams, you could record those attributes before writing down your dreams. But a lot of that you could do without even writing down your dreams, and I don't think many people actually do that. I wanted to and tried at first, but it became too much of a hassle.

Other than that, if neither of the two reasons apply to you, I don't see a reason you have to keep a dream journal. It's true that most people keep them to improve their recall ability. You still might want to write down your lucid dreams, once you start having them, maybe so that you can share some with others sometime in the future.