Lens manufacturers say that anything other than a microfiber cloth will damage the coatings on a lens. But microfiber cloths eventually pick up crap and they look like they're a pain to wash.
How do you keep your lenses clean? Are you using cloth/kleenex or microfiber cloths? If you use microfiber cloths, how do you clean those?
Hot water can damage your anti reflective coating. It can cause it to come 'loose'.
The rinsing is indeed done to get rid of sand or dirt particles which is the main cause of scratches.