Not really. I don't have an IG account, but when picking a place ein an area I don't know, it is the place to get an impression of the place. The visual part tells a lot about the place, while many websites maybe got a photo from the outside, if at all.
Google maps works the same way, thats the default in most of the world. I don't even know anyone who has IG account, myself including. Everybody has google account, not that you need one to browse (more or less) categorized photos on maps.
How do you even know that a restaurant exists in an area you don't know? Not through Instagram, but through a web search or Google Maps.
But you're right, having a ton of good images on your website is one of the most important things for restaurants and most other businesses. And most fail in this aspect.