I use them all the time - they work just fine, and nobody here has died yet (at least not from the banana leaves - can't rule out my cooking as a cause of death!).

Diana, Bubba-I've taste-tested leaves of Basjoo and leaves of "edible" banana plants side-by-side, and I think they're really quite interchangable for flavor. But then, that's just my opinion. Ever done a side-by-side, bubba?

I have used basjoo leaves for cooking. However, I personally don't think it contributes the same flavor as some edible varieties. I noticed that in Thailand where there are a lot of banana varieties to choose from, people only use a few varieties in cooking.
But go ahead and try it. I think it's better than using foil:-)

I've never noticed much difference in the flavor among varieties (I don't think any of them contributes much in that department, anyway- it's mostly an aesthetic thing.) And I still wrap the whole deal in foil before putting it on the grill, since I have a cooking attention deficit and the banana leaves are really easy to burn. I figure as long as the Al's not touching the food we're going to eat (nobody actually EATS the leaves, do they?), and serving more as structural support and insulation, it's okay.