Boruto: Naruto Next Generations was billed as the hotly anticipated continuation of the Naruto story yet, so far, the anime has been mostly filler episodes. Without question, Masashi Kishimoto's Naruto series is one of the most internationally successful anime and manga series of all time, but when the final arc began airing in 2015/2016, many viewers were disappointed to see the manga's final battles endlessly punctuated with long sections of filler that either comprised of old material or harked back to Naruto's childhood. The end of the Naruto manga received a mostly positive reaction, although it certainly didn't please everyone, but whatever impact the story's conclusion had was nullified in the anime by the constant interruption.
Many speculated that this was a ploy to give animators time to prepare a brand new Naruto series and, indeed, Boruto: Naruto Next Generations was soon revealed to the world as the next installment in the franchise, albeit one with considerably less involvement from Kishimoto. Boruto was released in both manga and anime format and immediately had fans hooked with a red-hot flash-forward opening that saw an older Boruto Uzumaki fighting a mysterious opponent in a ruined Konoha Village, with Naruto supposedly already dead. However, from this shocking opening, the anime and manga took very different routes.
With the exception of a few weaker arcs, the Boruto manga has been warmly received as it works towards the flashforward scene depicted in the very first chapter. The Boruto: Naruto Next Generations anime, however, has been almost entirely comprised of the same kind of filler that plagued the end of Naruto Shippuden, apart from an exceptionally animated retelling of the Momoshiki story and an adaptation of the Scarlet Spring manga. Essentially, while the Boruto manga has been introducing exciting new villains and exploring fascinating new ninja powers, the anime has been focusing on Kakashi and Guy's Hot Spring vacation tour.
While filler is an unfortunate part of any weekly anime series, it's unusual for a show to be almost entirely of anime-only material right out of the gate, like Boruto has been. One reason for this is that while any other new anime series would need to build up an audience with a run of quality episodes at the outset, Boruto already has a passionate ready-made fan base and therefore there is less pressure to rush into adapting the quality, canon material from the manga because Naruto fans will surely stick around regardless.
The exact reason why TV Tokyo and Studio Pierrot would want to delay adapting the Boruto manga is somewhat more complicated. Perhaps the most significant factor is that while most manga series can run for dozens, or even hundreds, of chapters before being picked up for an anime, Boruto began in both formats almost simultaneously. This means that while any other new anime would have a trove of source material backed up, the Boruto series does not and the current glut of filler is an attempt to play for time and allow a decent amount of manga chapters to accumulate before that material is adapted. Boruto being a monthly manga series doesn't help in this regard.
The second issue is one of whether filler material is automatically omitted as part of the true Boruto story. Illustrator of the Boruto manga, Mikio Ikemoto has stated that while the anime is being structured to avoid overtaking the manga in future years, the two mediums are telling parallel stories and the entirety of the anime should still be considered canon. Whether this is pure marketing spin or a creator's genuine vision is open to interpretation, but since the Boruto anime and manga started at more or less the same time, it could perhaps be argued that one doesn't take precedence over the other, unlike most series where the comics are always king. Therefore, while many of Boruto's animated adventures undoubtedly take a filler-ish approach, it's possible that these arcs are fleshing out certain characters in ways the manga cannot, and this could pay off in the long term.
Boruto: Naruto Next Generations is available on Hulu and Crunchyroll.