The market is not so big here so I would think certain client's security policy about localized data storage would play a role in their decision to build a center here.
I imagine Microsoft announcing a data centre here played a significant role - AWS wouldn't want to be the cloud service with _less_ regions than Microsoft.
There are significant AWS customers in New Zealand (Xero jumps to mind) that I imagine Microsoft would love to target with that differentiator of a local data centre.
However Azure regions are a single DC, while an AWS region is 3 Availability Zones ( each being at least a single DC), which is much much better for redundancy. Remember that time the whole of Azure's portal and O365 were inaccessible (nobody could log in) because some equipment failed in a single DC in Texas? Design for failure
