The difference is you're probably the only person who has ever said that about Carter the Unstoppable Sex Machine.
The album versions are Ethan.
I disagree. I prefer Ethan's cold vocals. He rarely sang in CC.
Robert Smith collabs with underground bands all the time and they're always great. This is the only collab that gained popularity though.
The original version has Ethan singing not Alice.
Ethan sings the other version of Not In Love through fx pedals. It's not Alice. Other slow emotional songs by CC include Violent Dreams (again not Alice), and Tell Me What To Swallow.