I would say if you are likely to listen to music from your phone or use other apps which are Carplay or Android Auto compatible then yes it is worth it. I have it on my 2016 Golf R MK7. I have used it a few times. But i usually use the SD Card for listen to my library of music in the car and the Nav Pro for Sat Nav. The time when it came in useful for me was when i only had my new music on the phone, not the SD Card yet.
However the only minor niggle I have found with using the App Connect, is not directly with App Connect itself but more with the setup of where to place your phone, as my phone is a little too large to fit in allocated area of the centre compartment so I have to drag the cable out through the opening of the centre compartment lid and place the phone on the cup holder cover.
With phones getting larger these days VW may have to rethink the positioning of the phones when connected to App Connect, as trying to use the allocated area I have broken so many USB cables. (For an idea of size, the phone I have is a Sony Xperia XZ3)