I think it means the language forces designs and eventually an ecosystem that's optimized around having cooperative multitasking as the only option. That makes

I think it means the language forces designs and eventually an ecosystem that's optimized around having cooperative multitasking as the only option. That makes dealing with concurrency an easier task since every library you depend on also takes concurrency seriously. And since cooperative multitasking is much much more efficient than preemptive alternatives, you end up with applications with great efficient concurrency support by default.