Here is the article they've written about it:
About 3 weeks ago, we announced that we started to accept Steem for our service at Bitwala. With a little help from our partner @shapeshiftio, it is now possible to pay any bank account in the world or use a debit card funded directly through Steem. In other words: Bitwala offers the first and only Debit card that’s funded with Steem!
… but nobody is using it!
They wondered whether it was because no-one knew how to use bitwala in conjunction with steem, so their article goes on to explain what to do - please click and read it.
I wonder why lots of famous steemit travellers like @heiditravels arn't using this system? I think it's likely because they simply don't know anything about it.