Bottle caps being attached is about the bottle and the cap being recycled/landfilled together instead of caps ending up in a different location. This works well with the return money you get for recycling bottles so everything gets disposed properly.

The general idea is that plastic in the environment is more of a problem than pollution from producing the little extra per bottle. Microplastics from plastics that don’t make it to the landfill are becoming a big issue and the EU is working on it.

Refitting machines to produce them is also not a big issue since that’s a one-time cost for not that many machines.