The tooling people have - as of about a year ago said they are ready. Now everyone who considers themselves early adopters is using then. Most are waiting for the early adopters to figure out what the best practices are so we don't make a mess
Nobody has said they are using them in anything important, but hopefully that is coming.
Whereas one kind of works (VS), there is apparently no work going on VSCode Intelisense, ticket is stalled since January, and the promised announcement never came up.