Probably more of the power users (brands and celebrities) that uses 3rd party analytics. Instagram is clearly trying to move people to their upcoming Analytics feature.
a lot of photographers (amateurs and pro) use instagram, they generally shoot on DSLR and then have to transfer to their laptops and then to their phone in order to upload to Instagram. I know this is not the majority of the users but its still a significant number. There are hacky apps showing up on both Windows and OSX that will do the trick but they are hacky nevertheless.
Instagram's api has always been locked down pretty tightly, not having near the use of 3rd party Twitter apps. This may not have that big of an impact.