It can be used without a smartphone. You can listen to the radio or connect a USB stick with your own music if no smartphone is connected, otherwise you also have Bluetooth. Navi is only available via smartphone (cable connection mandatory) as far as I could try it out, but would be happy if someone could teach me better. Ah, also note (with iOS) that no Google maps are used but your own (unless the phone "has" a jailbreak). I have installed it in a Golf 6 and am satisfied. For the price, you can't expect miracles, but you get a stable product with the basic functions and possibilities to expand it with iOS or Android (now at about -10'C it works perfectly). You would have to search Google for the software extension, I didn't need it and also didn't research it, so I can't answer the question.

Since this is an app radio, the logic naturally comes from the connected smartphone, otherwise it would be much more expensive...
I can confirm what my colleagues have written.
The radio is great, by the way, very good sound and reception quality but without DAB.
There are also extra navigation apps (App Radion, Car Play) that you can install on your smartphone for the App Radio. If you want to use Google Maps with navigation, this is only possible with the complete mirroring of the smartphone via HDMI.
I have no experience with Android.
Raffy: Thanks for the Mixtrax tip!