You nailed it.
The POD kicks ass for avoiding visits from 5.0 late at night, or even during the day depending on where you live. But, it just cannot equal the sound of glowing tubes overdriving 12" [enter you favorite speakers here]. I had the dumb luck and ambition to save up for a mesa boogie about 15 years ago and I'll never get rid of it. I've done a/b comps against the Boogie settings on the POD with my amp-close but no cigar.
I use the POD to initially capture ideas at low volumes when inspiration hits and then usually go back and re-record by micing my amp when the opportunity arises.
However, there are so many sounds that the POD does well that my amp could never get that I inevitably end up using some tracks from the POD.
It's an awesome tool, but if I could afford a soundproof room full of the amps that it simulates (my equivalent of the "if I won the lottery" daydream), I would have no need for it.
First and foremost, I am a guitarist, and manipulating all of the factors that yield great tone gives me great satisfaction.
dmc