You shouldn't choose because, of course, "Plotter" is the obviously correct selection.
I kid, but let me back up a bit: What are these terms?
Writers tend to use these words to describe the two basic types that make up their group. "Plotters" plan the story out in advance, and write to an outline. "Pantsers" make it all up on the fly.
So which is better? This is what I came here to explain: there is no choice. You don't decide which path to follow; you learn which group you are already in.
It's not about technique, it's about the way you naturally write.
Some will say that Plotters leave no room for inspiration to hit, or that Pantsers hit writer's block and give up too easily. Neither of these are necessarily (or even often) true.
Let me lay my cards on the table: I'm a Plotter. And how. I can't even start writing until I have every last beat of the story figured out. I just can't do it. (Or rather, I can't do it well, which is kind of the point.) If I try to write without a very sophisticated outline, the story just veers off into nowhere and I have to delete vast swathes of text and start again.
For me, a story needs to have a shape. I don't just put finger to keyboard and see what comes out. I know what comes out: nonsense. A story is about progression, about characters following their nature but encountering hiccups and overcoming them and developing in certain precise and entertaining ways. If you just let them bumble about doing whatever they feel like, it might be believable but it sure as hell won't be entertaining.
Ah, you may well cry, that is what rewriting is for. And this is true. Many writers find the story in the redraft stage and get everything into shape then. Me? I'd rather do all that pesky rewriting before the writing has actually started.
It's much easier to redraft a "beat sheet", or treatment, than a 90,000 word document.
But have I abandoned all artistic integrity by sticking to an outline? Have I hamstrung myself, leaving out all sense of inspiration and become a slave to a blueprint that I have bound myself to?
Not at all. In those cases where things start developing in ways that contradict my outline (and yet seem potentially more interesting than my outline) I see where that takes me and develop a new outline where necessary. (Or else realize I was right the first time and return to an earlier file which I conveniently saved when I began to deviate.)
Similarly, Pantsers are not necessarily more prone to giving up due to writer's block than Plotters. We Plotters have the same writer's block - we just experience it earlier (in the planning stages). Pantsers, in some ways, have a better reason to just plow ahead and see where the story takes them; if a plotter becomes stuck on how to implement his or her outline then it becomes harder to just power through the blockage.
So neither is necessarily beneficial. There is no reason to choose between the two, based on merit. What is important is to find out which of the two you are and do so quickly. The more time you waste following the wrong technique, the harder it will be to write anything half-way decent.
I legitimately do not understand Pantsers. How is it possible to craft a comprehensible and entertaining story without knowing where everything is leading? There are so many strands to a novel that I do not see how a writer can cause them to artistically convene and converge in any kind of believable and satisfying manner by doing it on the fly.
And yet it is done. Again and again, every single day, by artists whose talent is far above my own. I couldn't do it, that is for sure. It's not about choosing, it's about discovering. And I discovered very early in my life that I can only produce a satisfactory story by doing all the donkey work up front.
You may be the opposite. You may find that any outlining you do results in a mundane and predictable story that satisfies no-one, and the only way to create something of worth is to sit at the keyboard and figure it all out as you go.
It's not a choice; it's an identity.