Gorgonzola_Willywa

It makes more sense later in the chapter - each packet contains enough medicine for three doses, one dose per day. That's why each packet lasts 3 days.

Each character corresponds to an entire English word. When you consider it like that, it makes sense, especially since we have more than a hundred thousand words in English, even though only a few thousand are commonly used. The Chinese system is just inefficient in other ways, such as not knowing the pronunciation of a word just by looking at the character. However, once you learn the basic set of characters, it's often possible to guess the meanings of words you don't know by analysing how they're written and the context in which they appear.

Aah, the author finally remembered that cooking is also a skill

No, he earned 5 taels from selling the painting to the courtesan's maid. Then he earned 10 taels from the painting of the dying old rich man. Then, on the streets, he painted 6 paintings, charging 3 taels for each one, making it 18 taels for the street paintings. On the way home, he said he had bought some things and spent some money, so he only had 18 taels at the time when he was robbed by the two thugs. Then he "recovered" 48 taels from the thugs after killing them - his original 18 taels, plus 30 taels that was their savings. In total, he made 63 taels that day - 33 taels from painting and another 30 from the thugs.

The author isn't smart enough to realize that cooking, skinning, butchering and all these other tasks also count as skills.

It's pure plot armour, for the author to find a way to make a production-type job useless unless you have the MC's plot armour. Otherwise Mechanics would actually be useful to everyone on the battlefield, and the author couldn't go around claiming that his MC struggled by awakening a "useless" profession.

It sounds like there's only one God - the Illusion God - and all professions and powers originated from him. So the powers don't need to have any relation to illusions. Instead, the Illusion God is probably the one who created the world through his powers.

The identity of the protagonist of this story, because of the transmigration and the system

It's weird because it's a Chinese author using Japanese names