Well honestly there is no guarantee your bank which holds your cash will get robbed, bombed or something. EUR USD any other currencies... There will always be thieves and scammers. And dont tell me dollar didnt have rough time. There are currently probably over 100 000 companies who are stealing money from people as we speak, bitcoin or any other crypto is no exception. It is how it is. In the end you can keep ur cash with you in your wallet and hope nobody will beat you up and steal your wallet or you can put them to bank and hope it will not bankrupt or anything else. Speaking of crypto you can keep ur coins in multibit hope ur pc wont crash or ur apartment wont get robbed..or put ur coins into bank or whatever online and hope for not bankrupt or other. Its life. Get used to it.
Yes, thieves will go after anything with value. My point is that bitcoin is not mature enough yet and we have very few legitimate/professional investment options within bitcoin. One day we may have many options, but as it stands now, we do not.
As a side note, if you properly secure your coins, no one event (pc crash, ect) will cause a loss.