Have you read any of the sources you linked to? They debunk most of what you just said. "Ultra pure" water is very slightly more "watery" than regular tap water. Any effect that tap/bottled water has on anything, "ultra pure" water can at most have about 1.01x that same effect.
> water mains pipes last longer if its delivering hard water compared to soft water
This is the one thing that may actually be true, but it's because the minerals in the hard water build up on the inside of the pipes over time, creating a protective layer. This is especially great for lead pipes, as it can prevent the lead from leeching into the water.
> water mains pipes last longer if its delivering hard water compared to soft water
This is the one thing that may actually be true, but it's because the minerals in the hard water build up on the inside of the pipes over time, creating a protective layer. This is especially great for lead pipes, as it can prevent the lead from leeching into the water.