The rewards rate for $1 = 10 OCBC$ is not only for online. You get 10X points when you shop at retails for babies and children's wear, clothes, bags and shoes, department stores, electronics and gadgets; which cover almost all retails.
Why I think this win against Citibank Rewards is because of its points redemption. I'm a fan of cash redemption using points.
Citibank Reward is $10 rebate for 4200 points; while OCBC Reward is $10 rebate for 3600 points. On a long run, you get more rebates :)