Would you have been able to return to the airport in those conditions?
I'm guessing only the presence of an ILS or another airport nearby that had better weather would have allowed for a return if one had a problem after take off.
If for some reason my usual policy of not placing myself under pressure to depart for a particular reason had failed, and I really needed to leave then yes I would depart. Obviously one could have an engine failure in the soup but there is nothing from an instrument flying point of view that makes that take off impossible.