The advantage of WebGPU is that CPU time is very low. Depending on your computer, the demo may run at 60fps in WebGL, but the CPU time will be much higher than in WebGPU. As your budget is 16.6 ms per frame (to run at 60fps), reducing the CPU time will make it easier to stay below this threshold.
I’ve run the demo several times and didn’t get the error you’re reporting. What operating system/browser are you using to run it?