As far as the value of IG, it's a platform that makes it easy to communicate to a far ranging audience quickly. I'm sure that's why many use it, from enthusiasts to course designers, who use it to chart the progress of their work, announce new projects or tout completed projects. As far as misinformation or accuracy goes, IG is no different from the internet in general. There is no fact check system to ensure content is accurate. It's up to others to correct it but since it's no different from any social media or internet platform including this site, I don't really see anything unique with IG in this regard.
Personally, I go to great lengths to make sure anything I write on IG or on my site is correct and I'm sure that's the case with others as well. If I don't get something right, I'd hope someone would correct it and if it ever happens, I'd be quick to clarify, which is exactly what seems to have happened in the OP's example.
It's simply another platform to discuss what's discussed here.
In terms of influence, that's an entirely different discussion. In my opinion, there's so much that goes into influence and perception nowadays that IG is only a very small part of it. But architects, design companies and yes, even golf clubs are recognizing it and using it to their advantage.
So much more information and dialogue now on course design, which I see as a good thing.