The control center wifi control always worked this way. It wasn't "altered", that is a primary feature of its functionality.

Apple gains nothing from your WiFi re-engaging. But many users do because, as another comment mentioned, people turn it off in control center because their connection is temporarily shit, or more likely just accidentally. Then they get to end of month and they have a monster cell overage.

Someone was using control center wrong (despite it very clearly indicating the use of the button). It's a learning experience.