Well their primary use right now is as a store of wealth or a way to transfer value freely anywhere on the globe.
50 WDC is only about $1.60 of value right now but I can easily send it to anyone taking me up on the offer and I pay no transaction fee and it is almost instantaneous. Madfranks payment was fully confirmed in under a minute. WDC is blazing fast.
Think of it as way to work around the banks high user fees and potential future capitol controls. I would never pay $10+ to a bank to wire $1.60.
Once crypto's become more mainstream you will be able to to purchase things with them but that could take awhile.
WDC is fast enough to be processed at real storefronts. BTC is slow and to be used for regular purchases like a cup of coffee or something would require a middleman to process transactions.