(Ref 2018 SP5, so maybe interactivity is enhanced in newer versions. I doubt it.)

View Mates is particularly useful when I return to a large assembly after some time, and need to identify which mate needs changed to enact a revision. Usually, I want to identify and rename a particular driving mate so that I can begin altering it repeatedly until I reach an ideal solution. I need to alter it within full context and not View Mates context, so that the components are not interfering with or intersecting other nearby components to which it is not mated.

However, I find that I cannot slow double click the mate to rename it within View Mates. Right clicking it does not include a Rename option, and Edit Feature cannot rename it either.

You can rename a mate, or select and copy its name to locate it by search filter after exiting View Mates, while viewing it in View Mates window, by clicking Properties which is available in its right-click context menu. The Feature Properties window pops up, wherein you can rename it or copy its name. I also add Properties button to my Assembly Ribbon for broader use, but it is already present in the RMB menu here.

Alternatively, you can also Comment on a mate from within View Mates. Its comment appears with mouseover, but it does not get a visible comment indicator within View Mates, even if Show Comment Indicators is turned on in the Tree Display. Apparently, View Mates is an additional context outside of Tree Display. Inserting a keyword into a comment is another method to create a searchable entity tied to the mate which I want to alter in full context. 

It would be nice if the mates within the View Mates window were as equally interactive as the same entities within the Tree Display, but it isn't. These two small workarounds cover a small UI inconsistency in the specialized View Mates context.