Apple Watch gets a lot of stick for being a “me-too” product, and fans who don’t see the need for a smartwatch assume the business is a bust. There’s this crazy perception that Apple Watch is just not selling — but that couldn’t be further from the truth.

The Apple Watch, alongside other Apple wearables, is now raking in billions of dollars every year. The business is huge. So huge, in fact, that it would be a Fortune 500 company all by itself, outselling supposed smash hits like Microsoft’s Surface tablets and the Amazon Echo.

Here’s why Apple Watch isn’t the flop you think it is.

When it made its debut, it wasn’t really clear who Watch was for. It was Apple’s answer to rival watches from the likes of Samsung and Google, but not a lot more than that. It had some unique features, but it didn’t help explain why we needed a smartwatch at all.

That’s still very much the case two years on, but despite being an inessential gadget, Apple Watch is selling incredibly well — and attracting new fans by the bucket-load. Alongside other Apple wearables like AirPods, it has bagged the company over $5 billion in the last 12 months.

Apple’s wearables business is now “the size of a Fortune 500 company” all by itself, according to CEO Tim Cook during yesterday’s earnings call.

The smallest company on that list — Burlington Coat Factory, a discount retailer — is doing $5.6 billion a year in revenue. If what Cook tells us is true, Apple’s wearables are pulling in at least that, if not even more.

Apple still won’t tell us exactly how many Watch units it has sold, so it’s difficult to establish just how much of that $5 billion+ came from Apple Watch alone. But we can make some educated estimates — and Cook did reveal that Watch sales have nearly doubled year-over-year.

Ben Bajarin, a principal at Creative Strategies, estimates that Apple sold around 3.2 million Watches last quarter. That’s a fraction of the number of iPhones sold — obviously — but it’s still a significant figure that makes this a key device for Apple.

It’s clear just how significant when you compare Watch sales to those of seemingly hot products from competing companies.

For instance, Microsoft’s supposedly stellar Surface laptops raked in just $831 million last year after falling 26 percent year-over-year. As for Amazon’s Echo speakers, the most popular smart speaker in the market today, just 8.2 million units have been sold in over two years.

Apple Watch is even outselling traditional wristwatches from the finest watchmakers. Thanks in part to a crackdown on corruption in China, sales of Swiss watches fell by 10 percent last year, making 2016 the worst year for the watch industry since 2009.

Rival smart wearables are also struggling.

Fitbit, which still holds first place in worldwide market share, saw its revenue fall 20 percent in the all-important holiday quarter of 2016. As a result, it was forced to layoff 6 percent of its workforce. It expects to make just $1.5 billion to $1.7 billion in revenue throughout 2017.

The perception that Apple Watch is a dud, then, is far from the truth.

“Watch has been a key category for us. We’re really proud of the growth of the business,” Cook said. “We’re very committed to it. It’s already a big business and we believe over time it will be even larger.”

AirPods, another important part of Apple’s wearables business, are also a big success. Five months after making their initial debut, demand still “significantly exceeds supply,” Cook said — which is why they’re so difficult to get hold of.

Those who do get their hands on them couldn’t be happier. Research from Creative Strategies shows that 98 percent of AirPods buyers are satisfied with their purchase, which is a new record for customer satisfaction for Apple. The original iPhone held a 92 percent satisfaction rate.

.