In lights with twist on/off mechanisms, epoxying the circuit provides crush resistance and protects the circuit from water, etc. This is the case for Wayne's sammies, Infinity Ultra, ArcAAA, etc.
I guess you're asking about the Aleph LE? I would say also to provide some kind of protection to the circuit, but I haven't seen one of these in person, so /ubbthreads/images/graemlins/icon3.gif