I hated it at first but once I realised the use-cases I changed my mind. When you have regulations telling you to keep hold of documents for 5+ years, and you want to digitise them, then communicating through signed XML documents is a pretty nice solution. The format is suitable.

I mean, we're not talking about Twitter searches or any such useless stuff. It's inter-bank transactions, direct debits, payment pre-authorisation, etc. Everything that you really do need a paper-trail for for years and years.