I think tl;dr is justified if it arises as a postscript in a subsequent edit. It is not ideally readable style, but if many people might be rereading the answer, they might find it easier to follow the changes to the answer.

Making the shortahd a clickable link, as I did above, deals with the unfamiliarity concern.

I would not recommend editing answers to eliminate this construct.

I think tl;dr is justified if it arises as a postscript in a subsequent edit. It is not ideally readable style, but if many people might be rereading the answer, they might find it easier to follow the changes to the answer.

Making the shortahd a clickable link, as I did above, deals with the unfamiliarity concern.

I would not recommend editing answers to eliminate this construct.