You definitely need one, because a flatweave rug will wrinkle up every time chairs move across it, which will be constantly. I like the anchor grip from rug pads USA, which is low profile, so appropriate to a flat weave, but does a good job of protecting the floor underneath. https://www.rugpadusa.com/products/anchor-grip

I'm putting in a flatweave rug under the dining table... should I do a rug pad? which kind?
Thinking maybe the beige grid kind that's cleanable. But maybe I don't really even need one.