I also use Silhouette studio for tracing stuff, IMO, it's a basic one, but the one that work best for most of my need.
Else, I use InkScape, but most of time, if it didn't work in Silhouette Studio, it dosent work well in InkScape either.
So, when all fail, I manually trace in AD V2!
there's some very strong software to do tracing, like the one I used to convert a very bad logo to vector (I think it was Vector Magic), but manual conversion work pretty nicely if you do it not too often!
My point was not that if it should be include or not in the software (I think it should)... only to point out that it dosent have the AUTO TRACE function, but you can still manually trace in the software.