The backplate is just for show, it doesn't have any other function. You can see that at the bottom of the following links:
MSI's Ventus 2X is a factory-overclocked custom design variant of the RTX 4060 that still comes at NVIDIA's MSRP of $300. Thanks to a compact design the card and its dual-slot, dual-fan cooler will fit all cases, and the lower power requirements will ensure that even older PSUs can run the card...
www.techpowerup.com
MSI's GeForce RTX 4060 Gaming X achieves impressive noise levels that are whisper quiet and temperatures are low, too. Unlike other vendors, MSI achieves that with a compact dual-slot card, which ensures it will fit into all cases out there, and PSU requirements are minimal, too.
www.techpowerup.com
8 GB GDDR6, 2460 MHz GPU, 2125 MHz Memory
www.techpowerup.com
121w board power limit on the Gaming X. The Ventus 2X OC is probably the same, since the non-OC model is capped at 115w.
2490mhz boost vs 2595mhz boost - debatable, perhaps irrelevant, since the gpu will overclock itself a few hundred mhz higher than what's advertised anyway.
Gaming X is by far the quieter cooler, but TPU does its noise test from 50cm away, which may not reflect how far you sit from your PC.
I guess Gaming X is worth the extra 40 bucks...