It actually might get that hot in WoW. It certainly does in "the Pathless".My daughter uses hers for mostly writing, email and web browsing. I doubt hers will get to 100 degrees. The most taxing thing she's done is World of Warcraft and she says that it gets warm but not hot. She says that it's the first MacBook that she's had that doesn't get super hot.
My desktop reports 26.2 GB of RAM in use, 34 GB cached.
Yet I believe there is nothing wrong with that if done sparingly. Degradation does not happen overnight.
And yet again, pro starts to actively cool somewhere past 50 degrees, I believe?
Heat also does not help with battery longevity and other electrical components performance\\longevity.
My take is that if one plans to get a MacBook for a long time, and there certainly will be gaming\\development\\other heavy usage -- it's better to go with 16\\512+ pro.
Unless you will switch in a year or two. Base air is really enough for now, excluding heavy continuous multitasking.