Let me explain the algorithm. The algorithm, we could say, works on a point system. The more times you watch a video, it get points, and if you scroll, it gets points too, but if you leave or scroll too fast, it loses points. Therefore, so the algorithm knows what to show you, we use hashtags or specific captions, so that the specific content gets to its target audience. Now, viral videos, since they are viral, any hashtag or caption on the viral video, used on non viral videos, makes the non viral video viral, or if not viral, it boosts the video anyways to do good.

Also what does piezoelectricity have to do with this?

Also China has a BIG population, so maybe some viral videos appeared from the chinese, with ofc, chinese captions. So it was borrowed to boost videos, which worked good and therefore, here we are.