Whilst OzRunways is a legal source of all your required charts, maps and documents, it cannot be used as a primary source of navigation information much like a TSO'd GPS would be. Having said that, it's still helpful (see below).
This subject sometimes sparks passionate debate in Australia, with some in the industry advocating traditional paper based navigation, whilst lots of other people see the benefits an app like OzRunways has to offer. An EFB, like any tool available in aviation, can really help make flying easier and more enjoyable, but the EFB is not a panacea - it has its limitations and use as a source of navigational instrument is one of them.
The little aircraft icon on maps & charts is derived from the iPad GPS which is non TSO'd. Think of it as the equivalent of a VFR GPS.
AIP GEN 1.5 says the following about non-TSO'd GPS's:
8.5.4 VFR Operations 22.214.171.124 GNSS may be used under the VFR in the following applications: (a) Visual Navigation. Pilots operating under the VFR may use GNSS to supplement map reading and other visual navigation techniques.
Talk to your flying instructor or chief pilot about how to interpret "supplement map reading". We strongly encourage pilots to maintain good traditional map reading skills, and use the OzRunways GPS position to assist you in this regard. But it must be remembered OzRunways position information is not a replacement for the requirement to fix visually or by use of an approved navigation system (e.g. GNSS, VOR, DME etc.)
Night VFR and IFR requires GNSS receivers to be certified in accordance with TSO-C129, C145 or C146. The iPad does not meet these standards. For these kinds of flights, the position of the icon on the map in OzRunways must be used only for situational awareness.