I didn't say you can log it (legally). You can log whatever you want, it's your book. You're the one who has to justify it in an interview.
It's not flight time. You get credit for that experience toward I believe an instrument rating provided you're receiving instruction that isn't logged flight time. You also can use the credit from a simulator initial type rating course toward total time requirements of an ATP for instance. It's still not flight time but you can use that toward the certificate you're applying for.
Litmus test:
How much fuel did you burn during your simulator session. If 0, no flight time.
You know that column in your logbook (usually on the far right) that is labeled "total duration of flight" or "total flight time" or something like that, you can put it in that column. Also it counts towards your total number of hours, sure it has it's limitations as you described but when you write your total number of hours the class D sim time is included.
Maybe I am wrong about it though, I never used a civilian class D sim so I did not have to comply by the FAR, in the USAF's class D sims we logged multi, day/night, simulated IFR (if appropriate), ground trainer, and total duration of flight.
I don't agree with the Litmus test, when you loose an engine on a single engine aircraft you can still log flight time while you glide, when you fly a glider you can still log flight time yet your not using any fuel.
