Not only is Smith a better player, but you mentioned efficiency, yet Batum only shot 42% from the field last year.
First of all, Smith is much bigger and should be able to get a lot of higher percentage shots. Second, Batum was dealing with a variety of injuries last year thanks to the fact that the Blazers have no bench whatsoever, and also the fact that Batum is charged with a Lebron-like role on the Blazers. He literally does EVERYTHING for them. If you take away last season's campaign, and he's shooting upwards of 46% for his career. Additionally, his 3P% and FT% is heads and shoulders above Smith's, and he turns the ball over less than Smith despite averaging more assists. Honestly, I could continue and argue that Batum IS the better player.
For now though, I'll leave it at that. I'll give you a pass since Batum is underrated and plays on the other side of the country for a small market.
EDIT: The poster above also makes great points why Smith is NOT more efficient than Batum.