>>3902782380% of the use is to add acidity to a dish. Acidity is a flavor enhancer, balancing out bitterness or sweetness. Acid will add lightness or "zing" to a bland dish, or moderate a sauce that tastes too "heavy". Any time you re cooking and you think "Huh the flavor of this dish is missing something" the answer is almost always "salt" or "acid", and while salt is straightforward, acid comes in many forms. Imagine a guacamole made without lime juice. It wouldn't be awful, but it's just salty avocado, not guacamole. It needs that acid. One of the easiest ways to add acid is a splash of vinegar. You could use something like citrus juice, but the fruit goes bad, sometimes you don't want the fruit's other flavors, and the shelf-stable bottled citrus juices suck in their own way.
However, distilled/white vinegar hash a harsh flavor/smell to most people, relative to the amount of acid it provides, and makes the dish taste like vinegar, instead of doing the job of enhancing other flavors. So instead, there are many other kinds of vinegars that carry their own flavors along with the acid.
Rice vinegar often already has some spices in it, and mirin has some sugar. Without those additives rice vinegar is going to be close to neutral (or as you say, "a meme"). Wine vinegar is used for many traditional European cuisines. Vegetable dishes tend to use it, as well as sauces. Try making a dish that has a sauce with white wine vinegar in it, but make the sauce twice: once with (even cheap) white wine vinegar and once with distilled white vinegar. You will immediately notice a difference between the sauces.
Apple cider is often used as a cheaper version of wine vinegar, e.g. in past eras without modern supply chains for groceries. A few recipes specifically call for it, but back in the day it was just a way to have a less-harsh vinegar without having to buy wine vinegar (if you even could).
