Good linen will give you a very nice, smooth surface to paint on, much smoother than canvas. Of course, there are no "benefits" of linen vs. canvas. It all depends on what you intend to paint on it.
If you are going to paint a landscape with very loose, rough strokes there is no need to spend the extra money on linen because canvas will probably give you a much better surface for that type of painting.
If you're going to paint a portrait or a still-life with a very fine finish, smoothing out all brush strokes, with high details, then linen will be your best bet because trying to get that kind of finish on canvas will have you pulling your hair out. Unless of course, you put about ten coats of gesso on the canvas and sand it down between each coat, getting a very smooth surface. But, if you can get that with linen there is no real point to going with canvas.
As for acrylic vs. oil priming, acrylic is more of an all-purpose coating on canvas and linen. It allows you to paint with acrylics, watercolors and oils. You could even do pastels on it. But, if your canvas or linen is oil primed you will need to stick with oil paints.