So here is my advice. Almost anyone under 50 years old is tech savvy enough to learn how to use a scan tool and probably owns a laptop or smart phone to use as the hardware platform for the scan tool.
Get a scan tool. Scan the car regularly. If the service engine soon light illuminates, then plug the scan tool in and read it. It's as simple as a $49 OBDII reader, or more expensive for a BMW-compatible scan tool (I recommend a BMW scan tool over just an OBDII).
Read the DIY and maintenance section of this Forum and/or get the Bentley service manual so you can learn about how the car operates, and where the problem areas are.
Armed with this information, you don't need to give away money for a pre-paid maintenance plan (you are just giving money to BMW so they can finance the business), and go to an independent BMW service shop for regular maintenance and to them also for unexpected repairs. If you take some time to learn and understand how your car works you are less likely to be ripped off by people who you take the car to for service and repairs.
Cars are not that difficult to understand how they work. You don't need to be mechanically inclined to understand how the various systems function. Learning how cars function will help you throughout the rest of your life. It only makes sense to try and fully understand something you use that takes a lot of financial investment and can endanger your life if not kept in proper working order.
Just my opinion.