I am sorry, I have never understood why someone would not get it?! The labor and parts alone with today's designed computers is going to cost nearly half a new computer. It is electronics after all, so not a matter of if it will die, but a matter of when.
Yes, but the key question is whether that failure will occur within the expected usable life of the system.
To date I have had:
2010 MBP13 -- still in use by my daughter
2011 MBA13 -- sold in 2015
2012 Mac Mini -- refurb bought in 2014, still in use
2013 MBA13 -- refurb bought in 2014, still in use by my wife
2015 RMB12 -- bought in early 2016, still in use
Out of the above I've had one hardware failure, the HDD in the MBP13. Replaced with an SSD and it's working fine.
AC+ is simply an insurance policy. Typically these are all intended to make money.
Now with that said, the move towards monolithic systems with major assemblies does begin to change the analysis since savvy users are less able to perform repairs (such as the HDD I replaced).
Another factor is the accidental damage coverage -- how applicable that is will vary by user as we each operate in different environments.
The wildcard in this as well is whether the buyer has access to a substantial credit card extended warranty such as the one that Citi offers. Without AC+, I'd have 1 year Apple warranty and then 2 years extended warranty coverage through Citi. If I were to spend the $379 for AC+ on a MBP15, I'd have a total of five years coverage -- the 24 month Citi coverage engages after AC+ expires. Worth it or not worth it? Depends on the individual's risk tolerance and ability to self-insure against repairs. If I had a major failure in four years would it really be worth repairing or better to just sell for parts and replace?
My point is it's not a slam-dunk decision. Makes sense for some, might not make sense for others.