The result of last ODI showed that Sri Lanka is not an ordinary side and must not be taken as for granted. Also if Sri Lankans have the potential which they displayed today then why not they showed it in first two games, why they waited for 2 consecutive loss to regain the form. Sri Lankans were in complete command of the game today, first in batting they scored 290 runs and then in bowling they didn't allowed New Zealanders to score runs. Chapman was the only New Zealanders who score runs today but his knock was not enough because of no support from other end.
This was a pointless match for the Kiwis at the end of the day which is why it's simply a consolation win for the Lankans plain and simple. Nobody remembers who won which match since they only focus on remembering the winners of the entire series.
This series result was pretty predictable thanks to which it ended up being another boring ODI series.