When would you want to use something like this over just ordinary postgresql?

Say you're trying to measure/analyze the use of a feature like clicking a button. You want to record every time a user clicks the button, their user ID, and some attributes of the user (maybe in bucket A or bucket B of a test). Later you'd want to be able to answer questions like "how many times was this button pressed?" or "how many unique users pressed a button?" or "how many times did users in bucket A press the button?".

Is that an "appropriate" use for postgres? Or is that the kind of "metrics" that a DB like Dalmatiner would be more optimized for? Is there a nice overview of the various kinds of DBs out there and what use cases they're optimized for?