Conscious, why would that make a difference? # evaluates as $chan does and produces the correct channel name. if you had said "$chan is actually documented as returning the channel associated with an event" then you would have had a point. however, # is also documented albeit not as clearly ("refers to the channel you are currently on") but thankfully the # symbol is one of the first thing newcomers to scripts encounter.

personally, i find the # more readable and noticeable in that if i'm scanning through a bunch of code, the # stands out as representing an 'output line' more so than $chan. in this particular case, i don't think there are compelling reasons to prefer one style over the other.