You can’t speak french without using it, because the gender of a word changes the gender of particles attached. Think as if in English there was a male “the” and a female “the”, like “mthe” and “fthe”. You can’t just not choose on of those to talk about fthe sun!

Gender in nouns exists to reduce ambiguity (in general, complexity reduces ambiguity), especially in times before widespread dictionaries or even the internet.

More ancient languages with more widespread use tend to be even more complex: think of latin, where particles are inserted within the word depending on their function in the phrase. It’s as if in English to say “I go to work” we’d say “I go workt”, but to say “this is for work” we’d say “this is workf” Again, more complex to be less ambiguous