Having extra throughput is nice but for the average joe, they aren't gonna see any difference between PCIe 3.0 vs 4.0 in FPS, we are not at the point where a single GPU will saturate PCIe 3.0.He did exaggerate but, PCIe Gen 4 video cards will definitely make a difference. Greater throughput always is a good thing.
TPU PCIe Scaling for RX 5700XT
https://www.techpowerup.com/review/pci-express-4-0-performance-scaling-radeon-rx-5700-xt/