Subs-manager with AppCache - opportunity for local DB cache?

I guess this is more a question for @arunoda but maybe one for anyone who has experience with packages.

I’m using meteorhacks:subs-manager in my app and also use appcache.
Is there a reason why subs-manager isn’t caching minimongo with appcache?

I know that I could add ground:db but it feels like a combo of subsmanager and appcache should be doing the trick already?