What makes these promos better is that they're all real substories. "The Bouncer" and "Prodigal Son" from YakuzaKiwami and "Another Haruka" from Yakuza 5.
Kiryu reuniting with the orphans after his time spent in prison, almost going to tears seeing how much they've grown. Taichi takes no time and gives ol' Uncle Kaz a hug with tears in his eyes. Keep in mind it's been over 3 years since Kiryu last saw them, taking the events of Yakuza 5 into account.
If you decide to sing "Hands" while doing Karaoke, the song then later on shows scenes of Kiryu being what is essentially being Haruto's father. It goes to show how much Kiryu has grown especially considering the earlier entry showing him at his youngest. It can certainly drive the viewer to tears, especially since you can only sing this song after clearing the game, further driving home how Kiryu has grown over his two decade-long journey.
Likewise "Tonight" has flashbacks of the time Kiryu spent with Nishikiyama in "0" showing that after all these years and despite what happened he still remembers Nishiki as an old friend.
There are a number of small sidequests in-game that lean toward Kiryu being quite fatherly and thoughtful outside of his growing relationship with Haruto; these include connecting with a young girl over her love of Haruka, and dispensing wisdom to a young woman seeking to become an idol, but not wanting to leave someone she loves behind.
Nagumo's HeelFace Turn is both this and funny, having him calling Kiryu aniki and swearing to help him no matter what.
When the Yomei Alliance shows up to kill Kiryu and all the members of the Hirose Family for revealing the secret of Onomichi, Kiryu tells Nagumo, Tagashira, and Matsunaga to make them regret messing with "our family". When Nagumo questions him on his wording, Kiryu reveals that he's felt like a part of the Hirose Family ever since he was introduced to them by Nagumo.
The New Gaudi bar's sidequest, where Kiryu becomes a regular and listens to the others trouble, they start referring to each other as a family by the end of the substory.
The ending of the substory "Sins of The Father". The cult from Yakuza 0 has been dissolved once more... and the true identity - and intentions - of Suzuki are revealed: He was the founder of Munan Chohept Onast all those years ago, and actually moved to Onomichi to reclaim his position as Guru.
Shizuko: I don't wanna get hurt... Michio-kun, aren't you... scared of pain?
Kiryu as Ono Michio: Yeah. Pain really scares me, too.
Shizuko: Huh? You are, Michio-Kun? Even though you're so strong?
Kiryu as Ono Michio: Of course. Every day, I try to figure out the best way to avoid pain. But sometimes, life forces you to push ahead and keep moving forward, even though it hurts.
Shizuko: Why push ahead, though? Can't you just run away?
Kiryu as Ono Michio: Well, that's always an option. In fact, it might lead to a relatively easy life. But if you always run away from pain, you might outrun your dreams, too. And hurt those around you.
(Later in the conversation)
Kiryu as Ono Michio: If you don't get this surgery and end up dying, how do you think your mommy and daddy would feel?
Shizuko: Well... Probably pretty sad...
Kiryu as Ono Michio: Are you okay with making them sad, Shizuko?
Shizuko: No... I don't want that!
Kiryu as Ono Michio: Right? If you're brave now, you can protect them from all that sadness.
Kiryu's letter to Daigo, apologizing for having dragged him into the yakuza life only to then distance himself from the Tojo Clan, admitting he saw Daigo as a son he failed as he never spent enough time with him. Daigo ends up referring to Kiryu as his father and honors his wishes to not avenge his death at the hand of the Yomei Alliance.
The finale; Haruka and her family return home to the orphanage and are recording Haruto learning to walk; he stumbles several times, but eventually succeeds, encouraged by his mom and a watching figure - finally revealed to be Kiryu, who slowly walks off into the distance seemingly content his family is safe. Haruka's final words - "You can do it. You can do this. Hang in there," seem as much intended for Kiryu and the audience as they are for her son.