Just to clarify some points:
1. If you have an iPad mini 4 NO GPS (WiFi only), you can use a Bluetooth GPS receiver to turn your iPad to a GPS capable device.
2. Go4 app, doesn't use Apple maps, but maps of another company (usually "Here Maps"). To show maps online (during flight) go4 app needs a connection to the internet (via WiFi, or cellular). If you haven't an internet connection during flight, you can cash map at home and it will be saved (this doesn't work well for me). Note, that everything written in this paragraph has nothing to do with your iPad's GPS capability.
3. If you have an iPad mini 4 WITH GPS (cellular models, or using a BT GPS as mentioned above) and you plan to use it with different DJI drones (as Mavics) you can have dynamic change of the home point (change it as you move), or use it with auto modes, as "follow me". I have used these with my Mavics, and don't remember if there are other functions using GPS of the device.
So
You can buy an iPad mini without GPS and cellular. It's cheaper.
If you see in the future, that you need GPS, just get a BT GPS receiver.
If you want to have internet connection in flight field, just enable WiFi spot, on your smartphone, and connect your iPad to internet.
If you want all the connectivity because you need it, buy an iPad with cellular (it has GPS), as I did, and pay some more money.
