The short answer is, a metric can't require a lot of extra work (or it should be turned down).
The key distinction is, "Does reporting on this metric (as defined) place an additional expectation on my role?" In other words, you can't sneak in work by making it a metric (you have to propose governance to do that).
So, as long as the role-filler already has access to the information in the course of energizing their work (and there may be some negotiation between the Lead Link and the role-filler on how the metric is defined), then they should report on it.
I think this answers [@mention:549059653907130620] question about Rep Link as well. Rep Link is only reporting, not taking additional work.