A use case where disabling paste events makes sense:
You want to expose the functionality to make a drastic change on some resource, identified by a string, to the user. Users want this functionality for good reason. It's not reversible, for legal or security reasons. This is a change that could easily destroy the user's company or cost it millions of dollars.
Text specifying what they're doing is insufficient, as users just click through without verifying. Even a checkbox does nothing to make them pay attention. Even an input where they specify what resource they're performing this action on isn't enough, as two users have reported that they just copied and pasted the id of the resource instead of typing it in.
Sometimes you want to break the consistent interface. I don't think "verify that you typed in the password you wanted to for some shitty small company's website" rises to that level, but there are legitimate reasons to drastically increase the cognitive load involved in simple actions by breaking the uniform interface.