But they manipulate those bits so quickly, they can accomplish useful tasks. In fact, some early computers were programmed by setting sequences of ones and zeros on front-panel switches. That's clearly the low point in user-friendliness and inefficiency. Programming languages were created to give us humans a chance to understand what it was we were telling the computer to do.
Programming languages incorporate several important ideas.
They abstract operations into a form that's more like the way people think, which makes programming easier. To divide one number by another is a simple concept that we express in a couple of symbols, but to a computer, that same task takes dozens of small operations. In addition, programming languages let us give meaningful names to things like variables and constants, which makes programs easier to create, understand and troubleshoot. At the lowest level, the zeros and ones of machine code aren't really a language at all. The earliest true language was assembler, and it was different for each type of computer.