Rather, the point is that using the "embed" function is the only easy way to post it anywhere outside of Instagram, itself. That's fine for a good number of situations, but it doesn't work for the majority of people looking for a photo-hosting service and seeking to present their photos in any context they wish. Now, I could do a little bit of HTML jiu jitsu and grab the source URL for posting on Creamy Middles, like so:
But the image above isn't full resolution; it's about one-third the size of my original photo, which, once I delete it from my phone no longer exists. Which means that Instagram is purely an on-network sharing tool and not a saving tool.
What if I want to save all my raw photos in the cloud? I could set up my Android phone to save all my photos to Google Plus, and share certain photos via Instagram, but then what happens when I want to share a high-resolution image? Instagram doesn't work for that. Google Plus doesn't allow hotlinking. (At least, last I checked, it doesn't allow hotlinking.)
You know what does work for any and all of these situations? Flickr.
I can share this image in whatever resolution I have, to my friends on Twitter or Facebook directly from my phone, and use any of a series of filters from Aviary. If I really wanted to, I could post my images to both Flickr and Instagram, but unless I'm intent on building an Instagram network separate from my Facebook network, there's no point in doing that, since it's easy enough to post Flickr photos to Facebook.
Which brings me to a question: If the primary reason to use Instagram is that it has a super-simple interface with cool filters, do people realize they're giving up storing high-resolution photos and total flexibility in sharing their images for that interface and those filters, and do they realize that those things are also freely available on apps that don't make them give up that control?