WARNING: The following contains spoilers for the latest manga chapter and anime episode of Boruto: Naruto Next Generations.
One the Naruto series' biggest criticisms were its many filler episodes, especially in the Shippuden era. Many anime stall for time by producing throw-away episodes that give the manga time to move ahead, but Naruto really overdid it. It wasn't until later in the series, when episodes about Itachi and Neji started airing, that fans actually accepted these side stories.
Now, while Boruto initially fell into the same trap, it has finally proven its filler episodes are better than Naruto, thanks to the prelude to the Kara arc and the Vessel Recovery arc.
Boruto really is adding depth in a most impressive way, starting first with Mugino. In the manga, he came off as an arbitrary ninja that Ao killed, especially as we didn't see him and Ao interacting in Konoha. This made it tough to glean an emotional connection from the pages, especially when it seemed like Boruto was in pain. Sure, he lost a comrade but he wasn't close to Mugino nor did he and Ao have any sort of deep relationship.
Well, filler changes that perspective totally by showing how both Mugino and Boruto were inspired by meeting Ao. In fact, Ao taught them more ways of the shinobi so, when he betrays them in the anime, it hits harder and places their pain in context. In addition, we learn in the anime that Boruto considered Mugino more than a trainer; he was a big brother, an insight into their relationship that was missing from the manga, one that makes everything feel more important.
Things such as Sumire and Boruto crushing on each other are also played up in these episodes, which makes her concern about the Vessel and Amado in the recent manga chapter resonate more. Without these episodes, she just comes off as a random shinobi keeping an eye on the mad scientist. But, when these episodes show it's because she cares for Boruto, it gives her a motivation and fans a reason to care. We also learn more about Kara's internal strife, discovering why Outers were killed by Koji Kashin, why Garo wants Kawaki's head and how everyone suspected everyone. This makes them a better group of villains, on par with the Akatsuki and giving us the perfect peek into why Jigen distrusts them.
Last but not least, the filler has teased how important Code is to Jigen. In the manga, Jigen passes his mantle down to the Kara teen but again, they barely spend any time together so it feels random. We just see Code hiding out with the Ten-Tails, but in these extra episodes, Code tries to win Jigen's approval, viewing him as a brother and desperately seeking out the traitors within to help him.
The way he hates Kawaki and how Delta calls him out on wishing the Vessel never comes back also shows he was jealous of Kawaki, so that when Jigen makes him the successor, you feel why he's this grateful for the opportunity. If you're just reading the manga, all of this is not present, so many events play out in a much more hollow way. The anime turns its standalone side-stories into indispensable character moments, and per these examples, Boruto has mastered filler in ways Naruto never could.
