The reason it seems funny to see the word "stuff" in a scientific essay is that it's very much not a French-derived word. French-speaking people ruled England for a while starting in the year 1066, and quite quickly in that region the use of French-derived English words became seen as a sign of high class. That sort of thing, once strongly established, becomes self-perpetuating.

That's why, even today, a police officer might say in court, "I observed the individual in the vicinity of the canine" whereas among family the officer might be much more likely to say, "I saw the man near the dog."

The first sentence is full of French. The second, Anglo-Saxon.

It's the same reason we eat beef and pork, but raise cows and pigs. The people eating the meat were upper class and thus used the French-derived words; the people taking care of the animals used Anglo-Saxon.