Yes - I've been quite disappointed by this recently. I'm trying to make something that can interact with embedded devices and wanted to use the web serial JS API.
Unfortunately it seems that the powers that be at Firefox have no plans to support it on account of privacy and security - which I half get, but, it appears to be an established standard in Chrome. The discussion surrounding it kinda sucked and well.
I tried it a while back to configure my keyboard but it didn't seem to work at the time, I think it is a nice solution to Mozilla's problems with the API though
Unfortunately it seems that the powers that be at Firefox have no plans to support it on account of privacy and security - which I half get, but, it appears to be an established standard in Chrome. The discussion surrounding it kinda sucked and well.