That's true actually because the instances do all the heavy lifting of federation. You would just need to query both instances for the list of comments and then render them in a single page. There are plenty of possibilities for data visualization here. It would be interesting to see, for example, where votes are coming from on a given post or comment. Or get an idea more generally of which instances are interacting with posts originate from your instance.
If you only want to compare 2 instances, that'd be an easy tool to write and/or integrate into a client.
That's true actually because the instances do all the heavy lifting of federation. You would just need to query both instances for the list of comments and then render them in a single page. There are plenty of possibilities for data visualization here. It would be interesting to see, for example, where votes are coming from on a given post or comment. Or get an idea more generally of which instances are interacting with posts originate from your instance.