The basic kit will provide you with that information assuming you and your half sibling are taking the test and sharing the results. The addional information you get from the higher priced kit includes the information you seek, plus additional information which is personalized to you and would not be helpful in regards to determining relationship to someone else.
If you knew a relative had a disease which could be inherited and you want to know if your DNA puts you at higher risk for the same condition then the higher priced kit would be helpful, or if you just wanted to know if you were at higher risk for a certain disease it could help determine that too. However, while this information can prompt you to be watching for symptoms of a particular condition, it doesn't necessarily mean you will ever have it so the health results have to be put in proper perspective because many factors go into determining whether you will develop a particular disease. Therefore, you must not read too much into the health results if you choose the higher priced kit.