@edziu-konczewski The reason is indeed due to technical limitations.
Android does not expose any way for third party apps to answer an incoming phone call, at least not using publicly defined APIs. It might be the case that Tasker uses some internal hidden private API in Android, but such use is discouraged by Google and might stop working at any time. In every Android release, Google blocks more and more internal APIs.
That said, if you are happy with Tasker, you can simply use the Flic integration inside Tasker to trigger whatever you want in Tasker by the click of a Flic button.