Is this any better than using pastebin? One may argue that banks are more trusted for storing money than pastebin is for data, but is there another reason?
When standing in court trying to prove that you wrote something at a point in time, the judge is more than likely going to accept a bank statement than pastebin.com.
As you can read in the translation of the original article[0], the difference here is that banks must archive data about bank transfers for at least 10 years (in Germany), and are obliged to hand out this information on request. PasteBin does not guarantee this and may also not allow you to store a private document.
When standing in court trying to prove that you wrote something at a point in time, the judge is more than likely going to accept a bank statement than pastebin.com.