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!!"
"'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 elvish Evoker, as depicted to the left