In a press release announcing the proposed buyout, Namco notes that D3 would benefit from Bandai's reach into other mediums (toys, TV, arcades, movies/music); the sharing of game engine technology; cooperative development of mobile titles; and the rights to use Namco-owned properties (characters, etc.) in its Simple series of budget games.
We'll let you know when -- and if -- D3 has tekken the offer.
Source - Bandai Namco plans D3 buyout [andriasang.com]
Source - Bandai Namco Q3 Management Plan [press release: PDF]