What are the benefits to racial motifs other than the appearance of the crafted item, if any? Do they offer different stats or bonuses?
The effects of the racial motifs are entirely cosmetic; the statistics of a given item will be identical no matter the style used in crafting it.
The only near-edge case where style can have an impact is in the 'Convert to Imperial' option given to players who purchased the Imperial Edition of the game; this allows such players to convert items in any style to Imperial style, but also immediately makes the item bound so they cannot trade it. This is, however, more a side effect of the conversion than the style; the stats on the item remain what they were, and this doesn't affect items crafted directly in Imperial style, only items converted to it this way.