Family Bible useless?

Just curious if this item has any effects whatsoever.

It’s a trophy item for completing the ambition, so like all other trophies it has no use.

I see. So the only way to get legacy items is via in-game ambitions then, correct?

Legacy items as in the ones giving stat boni? No. You can get those from a variety of stories, most of them unrelated to any of the ambitions.