They’re different tiers, but economy is the majority chosen due to the price (business is expensive for most travelers hence why they opt for economy even if its crap) and it depends on how long the flight is rendering the price difference justified. If on a short flight, then economy is ideal if on a budget. However, if you’re heading somewhere it’s distant: business is better at the expense of paying a lot more than economy.
Business on any flight over 4 hours, if I can make the points work. I’d never pay for it, but I do credit card churning and so it ends up being a free upgrade usually.
Being able to lie down and sleep on a 12+ hour flight makes it so much less exhausting.