I'm using the NAIPS app on a iPad and it doesn't seem download the GAF. Am I doing something wrong?

They are in the charts section, not the ARFOR section. Be aware also that the NAIPS app is a third party application that has nothing to do with ASA or the BOM other than acting as an interface.

Does that mean those who get weather from the app aren't actually getting legitimate weather and they are illegal now too? :rolleyes:

If the NAIPs App isn't approved by them, then yes Car RAMROD, it isn't legal for most purposes.

As I believe I've mentioned before, it isn't just the simple act of gathering weather, there are checks and balances that need to occur during that process for an approved source.

If it's not an associated App then anything that ASA or BOM change on their end they won't be alerted to necessarily, it means it's integrity is not at the same standard.

I'm not saying it's a massive risk, 99% of the time it'll probably work just fine, but you need to keep in mind there is a risk using unassociated Apps.

Aviators:

Straight from the horse's mouth:

Air Services Australia:
The National Aeronautical Information Processing System (NAIPS) is a multi-function, computerised, aeronautical information system. It processes and stores meteorological and NOTAM information as well as enables the provision of briefing products and services to pilots and the Australian Air traffic Control platform.

From CASA:

Weather Apps & websites

These days, we have excellent sources of aviation weather information including NAIPS, now available as an App for your tablet or iPad. If you have an internet connection, Airservices’ NAIPS is a well designed program from which to source aviation-specific information including your weather forecasts, last light information and restricted area briefings. However, for the purpose of operational flight decisions (pre-flight or in-flight), a CASA approved aeronautical information provider is required to be used, of which NAIPS is but one.

For added weather awareness, why not take advantage of modern technology? As well as the excellent weather forecast access in OzRunways and AvPlan, the Weatherzone Plus App is a really useful tool and uses Bureau of Meteorology forecasts. It’s important to note that Weatherzone does not provide aviation-specific weather, but it still proves its worth in the cockpit as an additional source of general weather conditions. There is an upgrade version, Weatherzone Pro, available for an extra couple of dollars, which includes features like lightning and wind streamlines, three-hour temperature and rain probability charts and high resolution radar images. Remember the rules, however. It is a tool that must only be used to supplement other approved sources of aeronautical information.

From this, I would say it is difficult to argue that NAIPS is "unapproved" or "unassociated".