Yes, there are some of the people on there who think they're top notch photographers when in actuality they are just another person with an iPhone, but there are some great photos on there! There's also those 'follow for a follow' people on there who follow about 34778554 other people, which I think kind of defeats the purpose.
I think, like facebook (which I don't use), it's a way to share your thoughts with others. You might see an amazing sunset (so many sunset photos on Instagram) or see a funny sign, and if you want to share that with someone else, all you have to do is take a picture! I guess the 'point' of it differs from each individual, but someone could just as easily ask what the point of Facebook is. Anyway, I mainly use it to share my art. ^^;