Filter action: "Label entire thread"

Filter action: "Label entire thread"

Hello 
Currently it is possible to manually "Label entire thread" in Thread View (related to this topic [1]). The only thing that one can achieve thorough filters is to label a single message, which makes little sense in terms of 'conversations'. 

Would it be difficult to implement a "Label entire thread" Filter action, which would allow to  automatically label entire threads?  This would emulate the Gmail-style labelling of conversations. Personally I use it for labelling all conversations in which I participate on mailing lists. 

What would you think of this? 
Liviu

[1] https://help.zoho.com/portal/en/community/topic/archive-add-label-to-entire-thread-at-once?