46: Grant of visa does not guarantee entry permission
You could also call this:
"Having a visa doesn't always mean you can enter New Zealand"
When you get a visa, it doesn't always mean you can enter New Zealand. Even if you have a visa, you might not be allowed to come into the country.
There are two exceptions to this rule. If you have a permanent resident visa, you can enter New Zealand. Also, if you have a resident visa that was given to you while you were already in New Zealand, you can enter the country.
For all other types of visas, having the visa doesn't guarantee that you'll be allowed to enter New Zealand. The immigration officers at the border will still need to check if you can come in.