The choice between a raised bed and containers usually comes down to how much space you have, what your existing soil is like, and which crops you want to grow. Both can work well in a New Zealand garden, but they suit slightly different situations.
Raised beds are the better option if you have reasonable ground space and want to grow a range of vegetables together. Root crops like carrots and beetroot need loose, stone-free soil to size up properly, and generally do better in a raised bed with a full depth of good soil than in a shallow container. A raised bed also holds moisture more evenly than most containers, which matters for thirsty or long-season crops like celery, cucumbers and pumpkins.
Containers earn their place for a few specific reasons. First, control: a pot lets you give a plant exactly the soil, drainage and sun exposure it needs regardless of what your garden soil is like, which matters most for herbs (this site's dedicated container herbs guide covers which ones benefit most and why). Second, containment: mint is the standout example of a plant that should be grown in a pot specifically to stop it spreading uncontrollably through a garden bed. Third, mobility: a container of basil or chillies can be moved to a warmer, more sheltered spot, or brought undercover if frost threatens. That's useful in Canterbury and Otago, where a late-season pot move can save a frost-tender crop that a raised bed can't.
mint is the standout example of a plant that should be grown in a pot specifically to stop it spreading uncontrollably through a garden bed.
Containers do have real limits. Fruiting crops like tomatoes, capsicums and pumpkins need a genuinely large pot: undersized containers dry out fast in a NZ summer and stunt growth, and pumpkin's sprawling habit makes it a poor container candidate at all. Deep-rooted or long-season crops like leeks and onions also generally perform better with the fuller soil volume a raised bed provides.
In practice, many home gardeners use both: raised beds for the bulk of the vegetable garden, and a handful of containers for herbs, mint, and anything frost-tender that benefits from being movable.