Yep, it's insurance. All insurance is priced to benefit the provider not the consumer.
I've generally eschewed Applecare and have yet to regret that decision across multiple ipads, iphones, and macs. On the other hand I bought tire/wheel coverage for my car and it's more than paid for itself in the first three years of the five year term.
I see that out of warranty battery replacement is
$200 for the rMB. Since I have a 2015 and it's the first year for the model design, as I approach the 1 year term I may pick up Applecare, though I'll go with B&H or similar rather than eBay so as to avoid any question with Apple. Or I may not. All depends on what think I'll be doing with it at the time in terms of keeping it through the AC term or not.