A frying pan or a saucier can absorb at least equal if not more heat than a wok at home stovetop. In fact, that is even true for many restaurant stove too. One can heat up a frying pan as burning red hot from a professional stove. Blacken a steak on a cast iron skillet is done at a high cooking temperature. Yet, it will be a challenge to make many stir fry dishes in a 12" cast iron skillet. I think the real argument for a wok is our ability to move foods very fast in it. Just this week I saute/stir fry some green peppers in my frying pan. It works, but it is just not as fast and easy to move the food around.
Bring up a cookware to high temperature is one aspect. Ability to quickly move them around (cook more evenly and prevent burning) in another thing. Fried rice is a classic example. These two videos are pretty good at illustrating this point, and I have shared at the ~1:00 min mark and 1:50 min mark, respectively.
I do have a wok. I have been cooking less stir fry and more simmering these days, but I still use a wok from time to time, especially for foods which I need to move very fast. For example, I would prefer to make scramble egg with tomatoes in a wok which is not a very high temperature cooking dish.
