Yes, your loyalty program card becomes attached to your credit card and you will increase your points by using them together. The base reward for the My Best Buy loyalty program and the credit card is 1 point per dollar spent for each. When used together you can earn 2.5 points per dollar spent which is only a bonus of a half a point.
However, be careful because the interest on this card is so high you would absolutely negate the insignificant half-point bonus if you do not pay the entire balance within the grace period of 25 days. You do not increase your rewards significantly enough to be worth the high APR. Using a major bank credit card that earns rewards in conjunction with the My Best Buy loyalty program is a lot less risky and can still double the rewards since most reward cards give you at least a point per dollar on purchases.