Stamina is a complete waste for a UR skill, and weaker URs can be outdone by idolized SRs just because they have scoring abilities. For example, the SR New Years Rin is more powerful than the earlier day Smile URs like Honoka because she has barely less smile but a scoring ability as opposed to a perfect lock in this case. True that the leader advantage is nice, but it isn't always the determining factor, as I've mentioned a lot, my pure team is my strongest even with leader bonuses added in, even though my Pure team is the one without a UR.
URs are so overrated
/rant
On a side note, URs in JP are more to be obsessed about, none of them drop below 5000 in their primary stat at level 80