Good question. Does it cover the battery? To what level? The devil is in the details on these things, what it covers, what it doesn’t, and how much of a deductible you have. From what I see from high mileage Tesla’s, there are but a few high dollar things (sans battery) that can go wrong, and even fewer that cost more than 5200 plus a deductible.
Generally, I’m not a fan of extended warranties for anything. They are provided by insurance companies after all. Overall, the business works in their favor. So I believe if you take that same stance, you will come out ahead too. You will be burned once or twice, but less in the large scheme of things and come out ahead.
Only you can make this decision. There is not a black or white answer. There is also a psychological component that is worth real value here. If it makes you feel safe, there is value in that. If you normally buy great insurance and extended warranties on things like TVs and electronics to feel “safe”, then getting your car covered is real value IMHO.