[mort96]

Maybe more developers would make use of it if it was open source, existed for other platforms, and available for languages people actually use on those other platforms.

[lukeh]

GCD is. NSOperationQueue is too tightly coupled to Foundation to be useful/relevant on other platforms.

[Tsiklon]

It looks like there's a working GCD port for Linux in https://github.com/apple/swift-corelibs-libdispatch