In laymen's terms as I understand:- a Jenkins pipeline consists of a number of tasks that flow in sequential order from the top to the bottom.

If you want to debug/investigate more closely a portion of a 'long pipeline', one must add conditional statements to disable steps from executing, after a certain point. Say, for example, I only want to run the first 5 steps in a 20 step pipeline.
 
It would very useful if each step in the pipeline had an IsActive flag or something similar, that would by default be set to True. By disabling a step, you can keep the tasks within an existing pipeline, however, they just won't execute unless they are active.

This allows the user to test parts of the pipeline without having to add/remove steps.

The task could be disabled/locked for edits in the UI if the IsActive flag is not checked.

I have read JENKINS-62384 and do not believe that this description overlaps.

I have only worked on Azure DevOps/Pipelines besides Jenkins and found this feature extremely helpful (and lacking in Jenkins). It allows you to add steps and just that can be disabled/enabled if you don't want them to exclude/run them respectively.

I hope you agree with this improvement.