The most obvious one being that it's a secondary, so if you have a long range weapon and want a shotgun backup, you can get it without having to spend an extra point on Overkill.
Others include a tighter hip spread by default than the other shotties, lessening the need for the laser sight, and a 5% faster knife speed due to its classification as a handgun.
As good as these advantages are though, you have to decide for yourself if it's worth not having a longer range compared to the S12, or having to reload one shell at a time.
I personally think it's worth it, but if the Executioner were to get a buff, I don't want it to be something game breaking. Maybe just increase the min range so it doesn't drop off so drastically or to give the fast mag reload by default.
One of the proud people that still plays Mirror's Edge to this day. Not changing my sig until DICE officially announces Mirror's Edge 2