I totally agree on all points and none of the patches I'm actually using has an Amp+Cab block in them.
Yet, when quickly looking for sounds, that block is pretty handy as it provides a (more or less) matched cab instantly, whereas you'd need to look one up separately using just the amp block (you usually don't want to run a Marshall style amp through a Jazz Rivet cab, do you?). Which, btw, is also why it'd be cool if we could save the default settings ourselves (or even block presets in general, which would as well come in handy for other more complexed blocks such as the delays and reverbs).