That’s just not true. Carrier insurance is neither better nor cheaper.
Let’s start with cost. Most carriers charge around $10/month for insurance. Over the course of 24 months, that’s $240, which is already $40 more expensive than AppleCare+. Then there are the deductible costs. Most carriers replace the whole unit, so they charge between $100-$200 deductibles. AppleCare+ only charges $29 for display damage and $99 for damage requiring a whole unit replacement. AppleCare+ is cheaper both to purchase the insurance, AND with its deductibles.
And it’s BETTER insurance for two reasons: convenience and quality. Convenience-wise, you have the option to get your phone repaired same-day at an Apple Store or Authorized Apple Repair location. Alternatively, you can get an express replacement through the mail (usually next day) by calling AppleCare. With carrier insurance, a replacement phone is mailed to you and usually takes a few days. Quality-wise, carrier options usually outsource with companies such as BrightStar and Asurion who refurbish devices with third party parts. They are known to Apple technicians as “Frankenphones” because of how badly slapped-together they are. Often the enclosure, display, cameras, etc are all after-market imitation parts that are notorious for failure or quality issues. Basically, it’s not even an iPhone. It’s half-iPhone, half fake, running iOS. With AppleCare+, you get a certified Apple replacement device that’s fully comprised of original Apple components that has a warranty.
Don’t be duped by the carriers. Their option is janky and more expensive. The ONLY benefit is that they cover lost or stolen. Cheers.