I disagree completely, all damage to the enemy team that will lead to a frag some people don't even wear down Reinhardt's shield which is like the basic thing to do when playing against a Reinhardt composition, you know what Rein and his team is without the shield? Easy clustered frags. Also you want to be doing this before applying ults from your own team.
I lost 2 rounds to a Torbjorn because no one on my team with a mid to long range attack bothered with taking out the turret even though I would block for them. Doing damage to turrets is great. You know what helps destroying a Symmetra based team? Flanking and killing all the turrets so your team can flood in. All of these things lead to frags but frags aren't the important statistic of the game as it is objective based. Incentivising the activity of chasing frags is contradictory to leading the player to win the game.
Widows usually won't burn this down which is fair in some cases as they're thinking they can auto remove somebody from the game if they poke out from behind the shield. However this approach requires your Widow to communicate that and for your team to be able to put out consistent damage from other sources. I don't even play Widow but I know the mindset from playing snipers in other games and playing against enemy Widows.