I'm keenly aware of the controversy of using 100% O2 which is why I was surprised to see it's use being advocated during my recent AN/DP class...
I have been using pure O2 on in-water decompression stops since the early 1970s on military, commercial, and recreational dives; for standard and surface decompression profiles. I have often used pure O2 for additional safety margin using schedules based on air stops when a chamber was not onboard. I fail to see any controversy since the practice has been in use well before Cousteau and Gagnan invented the demand regulator for divers.