Those other things you mention are very useful, curved screens not so much. I owned the s6 edge plus for a couple of days, I didn't fall in love with it. It was too easy to touch those edge screens and activate the phone, I found myself constantly doing that. The most functional aspect was having shortcuts and contacts on the edge, but you could do that with the non edge phones as well so I don't see that as being an unique perk to the edge models at all.
Honestly it felt like a gimmick to me as well. Now of course maybe someone will come along and make a killer app that utilizes that edge, but so far I haven't seen anything particularly functional about it, certainly not at the level of the other things you mentioned. It's great for design, beautiful and unique, and I think Samsung is smart to cater to those markets as in many aspects Apple products are a bit primitive functionally but beautiful and well made. Although IMO Samsung should have married the Note and edge series and consolidated all their money and hard work into a single model line, regular and +.