I see a lot of variance on people’s amp recommendations for products. It seems to me like a clean 1W into 32Ω is enough to drive the majority of headphones to 120db, which is extraordinarily loud to the point of being unlistenable. Tons of middle-tier desktop amps can handle going over 5W per channel at the same impedance and some even go over 10W. Are these wattages actually useful for anything? What wattage would set you up for any headphone, regardless of budget?
One thing I’ve learned going to headphone meets is that some people like to listen at volumes I would personally consider punishing. While I don’t think that’s a great idea if you value your hearing, I’m not their mom.
Then of course, there’s the marketing question. Moar watts, moar better - never mind that going from 2W to 5W gives you a pretty meager increase in perceived volume (again that exponential thing - you need a difference of like 5x-10x in power to actually get a meaty increase in headroom) and that the average person is probably never coming anywhere close to the headroom limit anyway.