Some of your cases position the power supply mount at the bottom instead of the top. What are the benefits of this?

The two major benefits of this design are heat isolation and noise reduction. By moving the PSU to the bottom of the case, the PSU will not take in hot air from the CPU and GPU, resulting in a more stable system and less noise resonance. A bottom-mounted PSU also frees up space above for additional fans, and offers a lower center of gravity for a more stable case when transporting.