I don’t think that the conflict is between teaching classes (doing my job) and attending conferences (self-centeredly blowing off my job). Attending conferences (either to present papers, or just to learn stuff that feeds into my teaching or writing) is my job, just as teaching is. Being a member of a scholarly community — including the part of that community that isn’t in Detroit — is a big part of what the university pays me to do.
I do think I need to add one clarification to what I wrote: when I ‘cancel’ a class, whether for Yom Kippur or a conference, I almost always reschedule it (one rare exception was last year, when we lost so much time due to having two hurricanes — but even there we clawed back to within 30 minutes or so), so we’re really talking about rescheduling rather than canceling classes.
I didn’t make this clear because it never occurred to me that there was another serious option. From some of the discussion that I’ve seen elsewhere, however, I gather that in some places ‘canceled’ means ‘canceled for good’. I think that’s much more problematic. And at some point, very quickly, you might even fall below the number of class hours required by the ABA.