Can someone give me a reason to buy Stellar Lumines rather than just buying more XRP, From what I have gathered about both coins Ripple is years ahead of Stellar in their project and they are trying to break into a trillion dollar industry, To me Stellar is just a poser XRP coin without the banking attached.

Ripple si trying to be a SWIFT killer, but SWIFT is trying to integrate with the blockchain world by partnership with decentralized oracles (Chainlink). So it isn't really sure that Ripple is such a secure investment (imho).
stellar is a platform, and some ICO's are coming that will use stellar as platform therefore will use this protocol, and will accept stellar as payment.