The reason the IPA has been the standard in linguistics and anthropology for fifty years or more is that even though "we all pronounce things differently," the number of individual sounds in the world's languages is still finite, and all of then can be described by how they're formed by the organs of speech. IPA allows the printed representation of a pronunciation no matter how a word might be spelled, no matter the language or the alphabet used.

Cut to the (simplified) chase: IPA reprsents every speech sound in the world with a specific, unvarying symbol. (There are additional, super-technical symbols if you want an even more precise transcription.)

Example: "k" represents the initial sound in "cat," no how matter how it's spelled and no matter what language it appears in. "s" is the middle consonant in "recent." The upside-down capital "R" in the standard pronunciation of "Rheinland-Pfalz" doesn't exist in English, but you can hear it war movies when the Nazis speak German. It exists in other languages as well, including French.

Ever hear of the !Xun language of South Africa that uses clicks? IPA has symbols for those too. (Hint: "!Xun" is not a typo.)