I feel like it's buying something new and exciting that not everyone has. I care a great deal about the details and have carefully selected most of my grow list, but there's always room for a couple of crosses and a few "wow, I'm the only one growing this one! Heck *I* don't even know what to expect" varieties. I've also found you can google some of the older ones and find people talking about them. And you can always ask here and get a virtually instant response about it.
But then, I've really discovered a love for non-heirloom heirlooms.
Heirlooms in general don't respond well to my technique (which is flawed and inattentive and more enthusiastic than skilled) and I find the modern cultivars are more forgiving and robust.
Not to rile any feathers, this is just my experience from my very limited attempts.