You can use them as body massagers for sore backs, legs and feet.
You can stare at them; marvel at their beauty.
You can use them as sun catchers.
You can use them as a personal safety weapon when physically threatened.
You can use them to make aquaintances wonder just what in the hell those things are in that glass case---but, they'll never be brave enough to ask.
And of course, the best and most desired use is to cum your brains out in a variety of orgasms: p-spot, clit, vaginal, g-spot...the opportunities are endless.