Smithing Expertise now gives additional 5 points to Smithing skill. However if you reach 100 in Smithing you won't notice any difference (no boost in smithing), but it works for lower levels.

Some might say that the original effect is not bugged, but there's nothing that could damage Smithing skill therefore restoring damage to it is useless.

It's not a big deal, but I have very basic knowledge about CK so I'm not 100% sure if it works as it should (stacking with enchantments, correct boost values etc.).