Here’s why I find this confusing:
I’d naively expect language like “New topics” to display topics that were created within some recent window of time, typically with the window configurable on that page. I think I’d expect this to sort this by the topic creation date by default, too.
I’d naively expect language like “New replies” to be akin to /latest, displaying all topics within which a post has been added in some recent window, and definitely sorted by activity. Or, alternatively, I could also reasonably expect that these are just the posts that are explicitly replying to me (either in a topic I created or a direct reply to a post of mine). I really expect different language — maybe “tracked replies” — to show me what used to be called “unread”. And it becomes even more confused if it sits right alongside “new topics.”
I think of my tracked/watched state as something different and completely orthogonal — and something more important to me! I’ve done something to these topics already, something meaningful. These counts are the more important numbers to me! They’re like “softer” notifications. So that’s really at the core of why I dislike this; it removes that visibility from my landing page.