Um… Because he’s Ian Holm? Surely that’s the only real qualification he needs.
Look, if fellow LOTR star Ian McKellen and thesping mate Patrick Stewart can look younger in X3 and Wolverine thanks to some digi-tinkering then surely the geniuses at Peter Jackson’s Weta company could pull off the same trick.
That way, we’d get Holm as Bilbo and the continuity would be perfect.
Why not him?
So far, the CG trickery has been less than convincing. Plastic, even.
While we’re pretty sure Weta could do a better job, we’re also unsure if he’d be up for the role, given that it would mean being a lot more active than his past Bilbo work. No sitting around surrounded by elves this time around. Well, not as much…
Entirely Unscientific Holm-Alike-O-Meter: