The fact that they are using WGPU, which appears to be a Python native implementation of WebGPU, suggests there is an interesting possible extended case. As a few other comments suggest, if one knows that the data is available on a machine in a cluster rather than on the local machine of a user, it might make sense to start up a server, expose a port and pass along the data over http to be rendered in a browser. That would make it shareable across the lab. The limit would be the data bandwidth over http (e.g. for the 3 million point case) but it seems like for simpler cases it would be very useful.
That would lead to an interesting exercise of defining a protocol for transferring plot points over http in such a way they could be handed over to a the browser WebGPU interface efficiently. Perhaps even a more efficient representation is possible with some pre-processing on the server side?