Exactly. My point being that everyone goes downhill at some point. So you can go really really fast (air speed, not ground speed). Meaning, the weakest rider imaginable can have measurable times spent in rides at speeds where aero matters a LOT.
I remember my commute to and from work when I traveled to France for 3 weeks. Luckily, the way to work was all downhill into the river valley from Nancy. So no sweaty worker showing up. But, with flappy work clothes I couldn't nearly hit the speeds I could in a race fit kit. Also, it was my cross bike and not my roadie. So slower still. It was also straight enough most parts you could have gone faster.
One morning a pure roadie in road kit caught me going downhill and in one part I was having to put out appreciable power while that guy wasn't even pedaling!
Of course the way home was all uphill. Lol. That took a bit longer.