Jamil's tripel recipe calls for 0.25 lb aromatic, so I don't think it's out of place at all. I haven't made it, but I've made other light beers that are primarily pils malt and have frequently included some vienna malt, munich malt, or aromatic. Seems like a reasonable thing to add if you want a little more a malt aroma than pils malt gives. It all comes down to what you're trying to accomplish.