Yup I agree, Having a demo for BS would be absolutely pointless. I wan't one as much as the next guy, but from ED's perspective, what do they have to put; the KA-50. With that said, someone is definitely bound to mod or get pass the restrictions put on it, such as perhaps the fuel limit, so that whenever you wanted to fly it, you could just fly the Demo!
It worked for flaming cliffs because you didn't actually get the Su-25T, but a good taste of it, the vanila Su-25 with AFM.
Anyway, It's been officaly stated that there would be no demo before release, but mabey one after.