It’s nice to have I-drive not least because it avoids you having the stupid oddment tray in the dash. But I never use it for sat nav.
It depends on how and where you drive and for what reasons..
For example
I mostly do structured runs with 4-10 other Zeds.
We're doing about 5 hours and 200 miles a day.
I run my MMI box with carplay on my iDrive with Google maps and with the voice integration and idrive knob its a breeze to easily and safely dynamically navigate to the next waypoit be it fuel station, cafe, turn etc etc..if things change it 'knows' the most likely thing I'm about to ask..so if say we had booked a Premier Inn at Thurso, if I push the idrive knob to select P it almost certainly will offer Premier Inn Thurso as a top 3 choice..so so easy..
However in a multi leg journey in car play you only see the first leg.
I put my final stop in the original idrive map and have audio off.
At any time I can see the quickest / shortest route to the final waypoint and if needed can go direct just by pushing a single button..then back to car play...utterly brilliant..
In addition because traffic info comes via different routes you get two shots at traffic/road closures as neither is perfect.
Also Google maps will often route you through side streets etc whilst idrive map seldomn does.
Became very clear when I followed a Forum member who was using a phone google map and over 5 days we went for many interesting diversions as unlike carplay or idrive you get little spatial context.
Of course if you never drive your car /only go 25 miles to the same old place you'll never apprciate it.