I don't recommend it. I had a service plan on my Sig four years ago. They don't do enough to make it worth it. Most things you can ignore, put off, or have a local garage do. With my new car, I don't plan to take it in any more. I took it to the Service Center for a roof rattle the first week, which they fixed in a few minutes, and charged me exorbitantly. I don't plan to go back any time soon. Flush my battery? Sounds like Nissan when they found out that no one was bringing Leafs in for service. I might go in every couple years. That will be over 50K miles. These are electrics, not gas engine cars.
I feel sorry for those who think the service center does some kind of magic, and that they need to protect their $100K investment. Even when the dash says to take it to service (like for 12 v battery), it's something most anyone can do. Like, 4 bolts. Oh, yeah, they give you new fob batteries, too. Another $5. Oh, and they check your logs. I'm not convinced.
I just yesterday drove too close to a wheel stop that had rebar sticking out the top. Pulled my bumper off the underbody plastic. I could take it to Service. 100 miles each way, wait around 4 hours, and a half dozen bolts. What do you think they'd charge? I have an appointment with my local body shop tomorrow, not next month. 30 minutes, maybe, he says. I will report.