This is also something I would love to know, it would make these factories/Task wrappers much more convenient to use, but I've not really seen @_inheritActorContext @_implicitSelfCapture in the wild yet.
I guess one risk is that underscored attributes are not technically stable and it is actively discouraged to use them (though I've seen many repositories use them anyways, like @_spi).
Edit: I found this quote about @_implicitSelfCapture in the review of SE-0304