The middle paragraph, translated to English:

Drinking warm water from the hot water pipe is only recommended to a limited extent. Because it has stayed in the pipes for longer due to the circulation in the hot water system. Circulation is necessary so that everything comes out of the tap hot enough to avoid legionella formation. On the other hand, depending on the cable material, substances can come loose. Even if the quantities are small, you should always use fresh water from the cold tap when preparing food.

So yes, you’re right. It’s not recommended to do.

It could, however, make a social trend for shorter fingernails (primarily on women, I imagine). Just meaning people are more likely to trim their nails shorter.