The comfort, amenities and services associated with flying transatlantic in business or first class add much more than a "tiny" amount to my enjoyment of the trip. It's not just the seat, the entire experience is fundamentally different. There is at least triple the personal and storage space, often much more. The seat makes into a fully flat bed. There are fast-track security lines, lounge access at both ends of each segment, availability of food and drink at the times I want to have them, pyjamas so that I don't have to carry my own or sleep in my street clothes, etc.

This said, if you don't value those things, if you wouldn't pay for them with money, there's nothing wrong with redeeming for economy class tickets.