Why is Instagram popular if it's almost impossible to find anybody

I had been courious why Instagram is so popular, and now I've registrated. But I think it has been in vain. How could I find anybody of the people I know personally, if there is a lot of people with the same name, and the profile photo is so small that one can't see anything of it. Like a flea. And there is no filter, for e.g. town. Then there is no sense in the whole thing, I think.