no its fundamentally useless because holding off angles is only effective against kids who wideswing everything which is exactly what the majority of players in DMs do. In actual matches, people use flashes, stuns and clear angles carefully before engaging in a duel. That aspect of of the gunfight is completely negated in a deathmatch. The only thing that you can actually improve from playing DM is gunfight discipline and strafing. Holding angles and awping in deathmatch will only make you worse.