Killian Hayes has cost the Detroit Pistons games
Both Dwane Casey and Monty Williams were put in difficult situations with Killian Hayes, as injuries and the ineffectiveness of other guards forced them to use him.
There's also the fact that he was the 7th pick in the draft, so each time he had a couple of good games, it seemed as if he might have finally tapped into the talent that the Pistons saw in him.
He's a big guard who takes care of the ball and can defend, things the Pistons have desperately needed over the last 3+ seasons, so it makes sense that both coaches leaned on him at times. It's not like they had a lot of other options.
But as good as Killian has been in some areas, he's been atrocious in others, namely shooting the ball. The NBA is no longer a place for guards who can't shoot and Hayes has arguably been the worst shooter in the NBA so far in his career.
Not only does he not make shots, he barely takes them, which makes the Pistons play 4-on-5 on offense when the other team doesn't even have to defend Hayes anywhere on the floor.
Defenses sag off and dare him to shoot, which has killed spacing at times and undoubtedly cost the Pistons both possessions and close games that they might have won had Hayes been any kind of threat to score.
Coaches are always going to be enamored with guards who defend and don't turn it over, but the continued insistence on playing Hayes, especially this season, has not helped the Detroit Pistons.