The problem is that "youtube mathematics" focuses on Hilbert's hotel and Aleph Nought, while actual mathematics as it's taught in unversities barely mention the

The problem is that "youtube mathematics" focuses on Hilbert's hotel and Aleph Nought, while actual mathematics as it's taught in unversities barely mention these issues. Infinity simplifies mathematics _a lot_ in proving things from the basics of calculus (i.e. analysis).