They don't sell anything as "masterclass" nor is the term used anywhere regarding their product.

They sell an email service.

What the parent meant was that the launch of their service was a "masterclass in marketing" -- ie. they promoted it very well.

Not sure if I understand you correctly, but yes I think that the marketing campaign should never ever eclipse the product in itself. That’s how I felt when they launched it. From a product marketer point of view it was great. But from the product manager perspective I felt disappointed.