This is called grammatical gender. The articles as redundant information are quite useful when there is noise around. Even if you catch parts of the article and the noun, you can eliminate a bunch of similar sounding words due to the partial information (eg in this thread about See being lake or sea based on gender)

This is found in several sibling languages of German and the evidence for it is quite strong for PIE (4.5k-2.5k BC). It could have started with just slight changes (noun inflections) to signify information for clarification or redundancy which then got formalized over time due to natural language development.

Even old English had grammatical gender, and the gender neutral ness is a recent development (as compared to evidence of grammatical gender). We have holdover words from Old English where we don't see the absurdity because of the loss of gender during the Middle English (probably due to incorporation of different dialects in cities like London and gender less appearing novel and thus cool to speak), eg: wife and woman have similar but differently gendered roots (wif (neuter) and wifmann))

Tldr is that when you hear/read just the noun or verb itself you can already infer a lot of information about who is doing the act and what is the act being done to.

For more informaion feel free to read about conjugation and declination.

Yes, it gets pretty complex.