"Don't drink from the hot water tap" is universal advice
You probably know sugar dissolves a lot easier in hot water than cold. That's because hot water really wants to absorb minerals a whole lot more than cold water.
Which means, hot water leaches chemicals from pipes much, much worse than cold water. We try to use low-leach materials for pipes, like PEX, but the amount is never zero. the point is, it's much worse with hot.
It's not just the hot water transiting through the pipes, it's also the hot water sitting in the tank. At the least, most tanks have a zinc "sacrificial anode" to stop corrosion of the tank proper, so that zinc oxide is getting in the hot water for sure.
So, the clever person thinks "If I use from the hot water tap, I'm that much closer to boiling and it'll save energy/time". That doesn't actually save energy (because hot water isn't free), and the saved time isn't worth the added leachate.
So water you are boiling for consumption should be drawn from the cold, always.
Further, the water which has been sitting stopped in the pipes has had time to leach. You are better off running the water flow for as long as it takes to remove the cylinder of water which has been standing in the pipe for hours. Unless you're in the American West...
Separate from that, hot water at the wrong temp breeds bacteria
such as legionella. This was something discovered in fairly recent science, particularly during the Flint water crisis. As such, it's currently considered best-practice to hold tanked hot water at 60C/140F.
This in turn requires anti-scald mixing valves on all water outlets - fortunately most modern "joystick / 2-axis" style faucets include those.
Needless to say, if 60C kills the bacteria in hot water, 100C will kill the bacteria in cold water.