Many supplements work well on their own. If you pair some of them up, you will find they are even more effective!
Peanut butter and jelly. French fries and ketchup. Movies and popcorn. Sure, you can have one without the other, but why would you? The two just make each other better.
You can also apply it to supplements! While there have been numerous studies looking into the efficacy of specific ingredients, many have also looked at supplement pairings and determined that certain couples help each other do their job more effectively than they do on their own.