Juventus if they get to win the Copa Italia will now have a trophy to hold on to this season and has aswell been able to qualify for the champions league next season so they actually didn't get to end the season terribly because they have been able to get a few things off the season but if they get to improve further, they are very likely to get better by next season and be able to get even more by the end of the season.
Yeah this season is not totally bad for Juventus at all because even if they have not been a serious competitor on this league but at least they have managed to secure the Copa Italia trophy and at the same time they have also qualify for the champions League next season so perhaps is indeed a great achievement because like you said Juventus will have something to hold onto at the end of the season instead of completely ending the season with an empty handed.
Atalanta on the other hand was actually supposed to be the winner of the Copa Italia but they could not utilize all the chances they had to score because if you follow the match you will see that right from the first half Atalanta had more good performance than Juventus but Juventus was lucky to have seen and utilize the opportunity very well, so considering the possession from when Juventus score their goal is obvious their wining was a narrow escape.