What is the difference between 16-pin and 24-pin for USB type-C?
24 Pins is the Full Featured version, populating all contacts.

As USB-C has many different usage modes, you don't always need all contacts, they are mostly required for alternate modes like DP and full USB-3-speeds.

The big advantage of the 16 Pin version is that it is better to solder, so if the Pinout hits your needs, there is no reason not to use it.

I just had a look at Hirose CX90M-16P:


If you compare this to the pin usage in Power Delivery Mode you see that only Pins GND: A+B1, A+B12
Vbus: A+B4, A+B9
CC1/2: A5, B5
are needed, so you are absolutely fine with the reduced version.