It seems to include and aggregate previous leaks, but I don't think a trivial dismissal is in order, for a couple of reasons:

1- It aggregates passwords together, which is not a minor issue, previously an attacker would have to collect different databases together, links to which which might be shortlived due to it being illegal. 2- There might be new passowrds, or information that was so obscure that they went under the radar, (maybe not even included in haveibeenpwned) 3- It brings the issue to popular attention. This is relevant for both the consumer which is now made even more aware of the problem of password hygiene, as well as for new attackers.