Hi. I don't know if this may sound non-sensical, and if that's the case, feel free to decline the task.

I was thinking that maybe we should be able to activate the blockautopromote action in a filter, while choosing to not disallow it.

Why?
Because it makes the contentive action a little more discreet. Especially if there is a filter that uses the throttle action to detect certain pattern of edits. It could be convenient to not disallow the edit for the vandal to not immediately know that the pattern has been detected and to not know that they're been blocked autopromotion based on the pattern, to disorient the vandal and prevent them from evading the pattern detection.

That's why I think this would be a useful option.