It is customary for me to enjoy an espresso (occasionally two) with a bar of dark chocolate after dinner. I sleep well not much later. 100s of thousands, if not millions, do this as a matter of culture.
But have you ever tried stopping caffeine and then comparing your sleep?
What if you think you sleep well now, but it turns out you can sleep so much better?
I'm not saying you will (I'm neither pro- nor anti-caffeine). But I am saying that unless you've tried it, you have no way of knowing. And I know lots of people who have improved their sleep in various ways, who thought they were sleeping normally/fine, and then discovered they actually hadn't been -- they just didn't know any better.
(And even if millions of people do something as a matter of culture, that doesn't mean it's good for your health. There are tons of cultural practices that are bad for health, or bad for a subset of the population.)
For lots of people, especially those with ADHD, a small dose of caffeine will help them fall asleep faster and sleep better. Instead of their brains bouncing around trying to fall asleep, the caffeine focuses it and let's them actually go to sleep relatively normally.
I personally have to make sure that if I consume caffeine in the morning, it's enough to overcome this paradoxical effect, otherwise I often end up falling back asleep.
I definitely can't sleep as well if I drink coffee after say 5pm. I also have quite an extreme effect of coffee when it comes to sharpening my attention and cognitive ability. Those of my friends who say they can sleep well after coffee also don't really report any significant effect on ability after a cup. I think it's two sides of the same coin. You get the good with the bad, if your caffeine receptor-thingies are tuned.
There is a huge blind spot in scientific caffeine research around habitual use. Every article you'll have read saying "don't drink coffee after 9am or you'll never sleep again in your life pinky promise" is based on the same type of study:
Take people who drink x amount of coffee, give them a large caffeine dose at a non-habitual time, and report that they don't sleep as well that night. Which is obviously not how caffeine is used in real life.
Few things have disappointed me as much as caffeine research. If we can't get something so direct properly studied, what hope does 90% of science have?
What if you think you sleep well now, but it turns out you can sleep so much better?
I'm not saying you will (I'm neither pro- nor anti-caffeine). But I am saying that unless you've tried it, you have no way of knowing. And I know lots of people who have improved their sleep in various ways, who thought they were sleeping normally/fine, and then discovered they actually hadn't been -- they just didn't know any better.
(And even if millions of people do something as a matter of culture, that doesn't mean it's good for your health. There are tons of cultural practices that are bad for health, or bad for a subset of the population.)