Tea also has noticeably less caffeine than coffee, yet it has been treated as an energizing drink since it was first discovered.
When you don't have any adrenal stimulants in your diet at all, even a small amount is noticable.
Caffeine also has a metabolic half life of roughly 5 hours in the body, if I remember correctly. A few berries might not do much, but surely a handful will be enough.
Somehow caffeine from Maté feels different though. To me coffee gives a fast spike and then comedown, while Maté's effect is more balanced, and lasts longer. And I don't think it's just caffeine content, because tea is nothing like that for me.
For staying productive for hours, nothing beats Maté for me (except stimulant medication).
This is why I routinely wean myself from coffee by drinking tea on most holiday weekends. I feel it helps me to dissociate less while I should be present with family, plus when I return to work I have much less residual caffeine and can hit peak productivity, crank out some code. Props to devs who don’t rely on drugs!
Tea bushes use an entirely different metabolic pathway to produce caffeine than coffee bushes.
Here is an article that further describes how we believe caffeine synthesis evolved in multiple land plant lineages.
https://www.pnas.org/content/113/38/10613
Caffeine synthesis involves several enzymes, but the enzyme family (called the SABATH family) involved in the final stages of its synthesis can trace its origins back to the first land plants. These first enzymes are thought to have been very promiscuous (capable of having activity with several molecules), partially contributing to how caffeine synthesis managed to evolve independently multiple times throughout the evolutionary history of land plants.