Zack Snyder's Justice League redeems many characters done a disservice by the DCEU, but also finds time to acknowledge the unwavering loyal service of a certain Alfred Pennyworth. The phrase "long-suffering" is often attributed to Bruce Wayne's British butler, and not without good reason. Not only must Alfred perform the usual duties of a manservant (serving tea and the like), he must also deal with Bruce's part-time job as the Gotham City Batman, patching up wounds and keeping the Batmobile in tip-top condition. DC comic books have honored Alfred in a variety of ways over the years (Damian Wayne's cat, for example), while Gotham rewards Alfred's hard work with a far more paternal relationship and some sweet action scenes, but the butler hasn't been so lucky at the movies.
Michael Gough's Alfred was restricted largely to butler duties, occasionally offering a sage piece of advice to Keaton, Kilmer or Clooney. Only in the rubbish Batman & Robin was Bruce Wayne forced to confront the importance of his family aide when Alfred became ill. Michael Caine's Alfred in The Dark Knight trilogy suffered a terrible time trying to rein in Christian Bale. Caine's Alfred was forced to assume his master's moral burden (burning Rachel's letter), while worrying like a parent every time the Caped Crusader hit the streets. His only reward was seeing Bruce eating happily with Selina Kyle in the final scene - though Alfred still probably paid for his own meal.
In a single line, Zack Snyder's Justice League successfully pays tribute to Alfred Pennyworth, and tips the metaphorical cap to his diligent DC service. When the Justice League assemble (no gimmick infringement intended) in the Batcave, Bruce introduces Alfred to his new friends by saying, "Everyone, this is Alfred. I work for him." Despite being very obviously untrue, Bruce's implication that Alfred wears the pants is an acknowledgement of his wisdom, intelligence, and importance to Wayne's entire operation, both as a businessman and a vigilante. In so many versions of the Batman story, it's clear that Bruce couldn't lead his double life without Alfred by his side, but rarely does Batman admit that. Ben Affleck's "I work for him" line in Zack Snyder's Justice League is a touching remark that briefly exposes the genuine love and respect from master to butler that all too often goes unsaid.
The line works even better in the context of Bruce and Alfred's relationship in the DCEU. Debuting in Batman V Superman: Dawn of Justice, Batfleck was a broken man still recovering from the death of Dick Grayson, and becoming increasingly violent towards the criminals of Gotham City. This inner anger meant DCEU Bruce was less outwardly respectful toward Alfred than, say, Adam West might've been. Alfred returned the favor too, insinuating that Batman had turned cruel. Even in Zack Snyder's Justice League after Bruce has chilled out, there's a still a little antagonism. Alfred vocally expresses concern over resurrecting Superman, and after the butler offers to make tea for the League, Bruce merely replies with "great." Not even a "thank you." Nevertheless, this rockier dynamic makes the "I work for him" pay off that much sweeter.
Ben Affleck's Batman is, like every member of the Justice League, much improved in Zack Snyder's Justice League compared to the 2017 theatrical version. The Snyder Cut does a much better job of exploring the guilt Bruce feels over Superman's demise, and his quest for atonement by bringing the Kryptonian back to life. Alfred's respectful introduction contributes to Bruce Wayne's road to redemption. After all, acknowledging loved ones is an important step in any journey of atonement. Batman is also a more effective leader in Zack Snyder's Justice League, and humbly accepting that Alfred is the beating heart of his operation makes Bruce appear more self-aware as he assumes leadership of his own supergroup.