Calculus is built on limits, not infinitesimals. At least, that’s how it’s normally defined. They both work, and neither was understood when calculus was discovered.
I think most people are fine using the tools without understanding the rules, and find that easier than learning the rules. Schools are built to teach the way that the majority learns best, as it’s better than teaching the way that the minority learns best.
Calculus is built on limits, not infinitesimals. At least, that’s how it’s normally defined. They both work, and neither was understood when calculus was discovered.
I think most people are fine using the tools without understanding the rules, and find that easier than learning the rules. Schools are built to teach the way that the majority learns best, as it’s better than teaching the way that the minority learns best.