In that particular case you're probably right, also because he's easier to summon than I am. On the other hand, if you summon me you're pretty much guaranteed to get the first hit since I'm spamming summon on one of you guys. Summon him and he's liable to walk off if your non-summoners aren't on the ball. He's also not vuln to all of your weapons like I am and parries better than I do. Plus you had someone to dispel me. If that dispel goes through then it's a repeat of the smackdown you and Mendecirith gave me in Voralian, only worse because it's not just you and Mende.