Why emulate POSIX signal semantics? Those are a holdover from the single-thread UNIX era. Events should be delivered by threads or async calls. Signals should be reserved for exceptions, things you don't return to, like segfaults.
Signals are useful as a software analogue to hardware interrupts, even though they are probably too low-level for most application use cases. They are for example used by the Golang runtime to preempt threads AFAIU, which wouldn't otherwise be possible non-cooperatively. Intel even included an ISA extension called user-IPIs, which is similar to signals.
