Sehr schön is a common German expression of approval, roughly equivalent to very nice or very beautiful, and it is widely recognised even by people who do not speak German. As a soundboard clip, its appeal is its brevity and clarity: the whole reaction fits into about a second, making it easy to drop into edits, streams and meme videos without interrupting the flow. It is typically used as a positive, slightly playful response to something attractive, skilful or satisfying, which is why it keeps appearing in reaction edits and short-form videos.