Bandai Namco Entertainment (BNEI)/Studios (BNSI) doesn't really have all that different of a corporate structure from Nintendo or other Japanese developers though. When BNSI separated from BNEI, the result is that pretty much all of BNEI's developers were moved to an operationally independent subsidiary. It's probably mostly a corporate leadership-related change and doesn't further clarify which developer worked on the game, cause BNSI is still just one developer, like Nintendo is one developer. They even took it a step further... Namco Tales Studio was originally its own studio responsible for Tales of games, but they were merged into BNSI.
In the end, BNEI is still responsible for the planning and producing of all Bandai Namco games (through their IP Business Divisions), but since they have no developers it kind of works kind of like a fully external EPD. This would be like if Nintendo spun-off all of their in-house developers (not just a Zelda team or a Splatoon team) to form a new company called "Nintendo Studios". Production Groups in charge of projects would still exist in the original Nintendo company, but now only work on an external basis with "Nintendo Studios", like they currently do with ND Cube and Monolith Soft.