I dunno. Seeing as how poetry is an art form that people can use to explore themselves and the world around them, from the absurd to the surreal to the very real and very serious to the wonderful to the painful, it brings out an analytical side in people. Seeing as how it's often a very different way of analyzing the world around you compared to relying on hard data and numbers, I can see how it could encourage people to be more versatile.
That said, if you think poetry is all about the egos of the writers, you must be reading some really shitty poetry. I haven't dabbled in it for over a decade, as I've just moved on to other things, but seeing as how it's an art form that had existed for millenia and has been an integral part of almost every culture with a written language, the sheer variety of work out there is mindblowing, and the depths and breadths of the subjects and concepts mankind has touched upon through poetry even moreso.