I think the reason it's indie games is because Suda himself has said he always has felt more like an independent game creator, and indeed he got started years ago by doing things differently which caught attention in games where he was assigned to odd roles, famously having his break for writing a surprisingly deep story for a wrestling game, then making niche cult hits like the Twilight Syndrome series and Silver Case, becoming far more known for bizarre games like Killer7 and No More Heroes... I think he lost some motivation which is why he hasn't directly directed anything since the original No More Heroes because he wasn't big on the bigger game development scene, he's always seemed more interested in being more free to create his own bizarre things rather than rise in the ranks and be assigned to bigger projects. However, if you listen to him talk about him and gaming in recent years almost all of his favorite games of the last several years have been indie game titles, and I think the reason why he's back to direct and No More Heroes in the form of it being in some ways a celebration of indie games is because he's been loving the indie game scene himself and found himself motivated to do something in that space. I'm guessing the reason for his return and the first thing he's doing is something No More Heroes related again is to show he's back, he's working on something he loves, and to give the whole indie scene he's been loving a chance to be part of a project of his I think he finds fun to direct.
It's just my theory, not directly said, but I think him not directing anything for 10 years, his expressed love of the indie game scene, the sorts of things he did direct when he was directing, and what No More Heroes: Travis Strikes Again turned out to be are all very telling.
I'm just amazed at the idea of No More Heroes turning into its own pseudo, stylish, and more violent take of something a bit like Kingdom Hearts but for indie video games.