Well actually there's no way Starbeam would send an asset like that out into the forefront. So it'd be less a mobile siege engine and more like a mobile defensive line.
"Yes! We're in the town! Let's start burning- AARRRRGH!!"
D&D is the only game I can think of (with the possible exception of Calvinball) where the only way to lose is by playing to win.
"'Elvish barbeque' is what happens when the Quessir send one of their Evokers to deal with an orc invasion and then go home for the evening." - Elmah Dryearghymn, an elven Evoker, as depicted to the left