I like the middle weight snubbies, the airweights. I wouldn't want one of the AirLites, with the titanium barrel with SS insert. Too light. Also heard that they aren't as accurate as the ones with steel barrels. To me, if I'm going to pack a 20oz revolver, I can add a few ounces and carry a compact Glock. So if the snubbie is going to be a backup, I would want it to be lighter than my primary.
I do understand what you are saying about being a lot lighter than an all steel medium frame. I have no problems carrying my 3" GP, so a 2" 60 would be easy. But I just can't justify the small gain in weight, for the loss of 1 round (almost 20%) and shootability.
I just haven't found too many occasions that demand a smaller gun than a Glock 19 or 3" GP that would allow a 20oz model 60. One of the few regular occurrences that preclude the larger guns is when I'm out running. Then I need as light as possible.
Which models are these? They keep making up words like scandium and such, it gets confusing. My 637 has an aluminum frame, is that what you're talking about?