Services such as map updates, internet radio, Spotify connect streams directly from the cars head unit (data). Updates for remote services often use SMS/call.
Cars that do this don't have the 3G only head unit, though. Newer models have things like properly integrated spotify and remote map updates, but they are also 4G as well so not a problem.
We're specifically talking about cars with NBT iDrive 4.0 produced between 2012 and 2016. The Spotify integration on these cars, through BMW Apps Interface, uses the mobile phone data and not the car SIM card.