Buying Steem or Steem Power directly with your bitcoin or ether is very easy on this site. It is also very easy to lose your cryptocurrency if you're not doing it the right way. For example, you may be tempted to test the deposit address given to you by sending an insignificant amount first (before sending any significant amount). But that would be a mistake because you may lose the second payment if you send it to the same address!
Here's how it works: when you click the "BUY STEEM OR STEEM POWER" button on your Wallet page then you'll see a dialog box where you can pick which one you want. You can also select your payment method: Bitcoin, Ether or Bitshares and based on that choice you'll see an address where to send your money.
Now comes the critical part: I recommend not to send anything to an address that was used before because that may not be safe. Instead, click on the "CHANGE DEPOSIT ADDRESS" button to get a fresh address. That button is there for a reason.
What happens if you forget to get a new address and reuse an old one? Well, your money will get there no problem but then it may get stuck at that old address and just sit there doing nothing and you will not see any additional Steem or Steem Power coming into your Wallet. (You cannot transfer it back to yourself either because you don't have the private key for that old address.)
So what can we do when that happens? If nobody has that old private key any more then that payment is gone for good. That's why I think it's best to get a fresh address each time by pressing the "CHANGE DEPOSIT ADDRESS" button.
We should keep in mind that steemit is in beta, so it may not always behave the way we expect. I haven't seen any official bug bounty program yet but I think we can still help by reporting here. I mean that we can help not only the developers to make steemit better but also the users by warning them what to do and what not to do on this website.
I think we can all agree that losing money is not a good user experience. Sending bitcoin or ether and getting nothing in return is not acceptable. Even a long delay is not acceptable because exchange rates can change so fast...
So what would be a good solution? One possibility is to copy what shapeshift.io does: if the order doesn't go through then return the user's funds to his or her address immediately (minus a small transaction fee). I think that would be an acceptable alternative if we cannot expect a 100% success rate. What do you think?