The whole point is to have a more convenient and same or higher level of security for unlocking your phone. Why do we have a fingerprint scanner if pattern or pin can still be used. Don't you think swiping up is quicker than keying in a pin or pattern? Iris scanning is one of the highest levels of security we have on phones right now.
Now I must say, I'm a little confused with your post. In one line you mention Samsung's increase touch sensitivity to use gloves. But then you say, once you unlock the phone with the Iris, the gloves would be a problem. You just explained gloves are not a problem.
I'll just explain, I'm wearing gloves. I get a message/email. Or I want to get on the phone and start checking undead emails or just browse the web. I use the fingerprint scanner like most people, because it's quick and easy. So the glove comes off to unlock the phone each and every time. Then it goes back on while I use the phone.
Now, with the Iris scanner, I swipe up to get my Iris scanned and bam, I'm in. Then start using the phone. Gloves stay on the whole time. I hope that clears up what I'm saying.