It's really not, though. The times that you perceive your cast bar finishing but the target dies anyway are attributed to latency normalization, which fluctuates greater than the different in cast time that 20 haste makes. It is a flaw of human perception that they know that they have an additional .06s per cast, and believe that therefore every time a heal barely lands, it must be attributable to that extra .06s and not a multitude of other factors that make a much greater difference than that haste.
Additionally, don't keep repeating that 100hp propaganda that that troll put out there, it's a gearing difference of approximately 230 to 360hp. If I as a rogue see one character at 1600 health, and another at 1960 health, who do you think I would try to ambush? Especially if one also has a ~750hp bubble on?
I appreciate the fact that we're at least back to debating the relative merits of 360hp increased survivability vs 6/100ths of a second of increased latency compensation, but again as I've said, this is a rehash and a repeat of what's already been said in the thread. Most people have fallen quiet because they have already decided which way is the better way for them personally. Neither side is WRONG, just one sees the benefit of marginally increased survivability and the other sees the benefit of marginally increased cast time. We could debate all night over how significant 360hp is, or how significant .06s is, but we've for certain reached a point where no one's mind is going to be changed, so let's talk about something else.