There are pros and cons. I am like you and err on the side of privacy and do not share much. Never had IG and do not like sharing here. That's on one hand.
On the other hand, it's hard to take technical advice seriously from people if I have not seen their work.
When someone says "use this or do this, works great!" my mind is sending that advice straight to the trash because 80% of the world is filled with poorly made stuff, I have not seen what "great" means for them, so I assume that with 0.8 probability it's garbage. From that perspective I wish more people shared their work, so I could be less dismissive of their opinions.
@hoffy back to the original topic: In my opinion, photography as an art form is deprived of appreciative audience. Photographs are simply not valued as much as paintings or music. The Photrio crowd may think that Ansel Adams is an artist, but every non-photographer I know believes that his work is only worthy of a waiting room in a dental office. I have long accepted that no matter how good you are, the world does not care. I feel so lucky that it's not true in my career field. I would have been miserable if I was a photographer. In that sense, sharing is pointless. IG is a marketing tool, I have nothing to sell, so I never saw any reason to share anything there. I shoot for the audience of one, and I learned to enjoy the process and the results immensely. It's liberating.