Alright, back on topic. Serious question. Why would anyone purposely sparge with hotter than 180F water?
When batch sparging, 190+ water may not even get your grain bed up to 170. I normally aim for 180° sparge water, but sometimes I space out and over do it. I once had it boiling but had a bit of left over RO water that I was able to dump in.
Why shoot for a grain bed temp of 170F for sparging?
In a true mashout, holding the grain bed at 170F for a period of time denatures/stops all enzyme activity, 'locking in' your mash profile (fermentable sugar profile). Raising the grain bed to 170F obviously requires sparge temps considerably hotter. Most homebrewers (myself included) don't do a true mashout - I got in the habit of doing it also thinking it might increase my efficiency a bit due to reduced viscosity at higher temps. I don't believe it does to any real extent, but I make good beer thanks to having a handle on pH. The astringency I got came at cooler sparge temps with lax pH control, ironically.