One unnecessary choice in Clock+, apart from not working, is that in order to allow pre-dismissal you need to enable pre-alarm notifications.
You can go into the list of alarms and click Dismiss, but only if that alarm has already popped up "hey, I'm about to ring in (e.g.) 8 h". These two things don't need to be coupled, why not just always show the Dismiss button in the alarm list and then you choose separately if and when you want notifications?
My use case is going to bed and knowing that "ok, tomorrow is special, so I don't need alarms X, Y and Z". It's not "oh, it says I need to wake up in 8 h, I forgot about that. Nah, I don't want that".