As
@Chris has said, Monitor is a nice to have but absolutely not the end of the world if it doesn't come with it, just might help resale.
I used mine on track at Bedford to record lap data, but I was so slow it didn't really mean anything. First and foremost it's a car, so will the Monitor change your A to B journey? Absolutely not. An example that has been well looked after is far more important.
What I will say is that the Bose option has enriched my driving experience, it's superb, and I didn't even know I had it until I left the dealership! You lose a little depth in the boot but that's it.