Not that expensive imho, certainly compared to some tech conferences.
Plus the connections you could make there could be far more valuable than 400 euro.
I agree with you. But I wonder is this event the most worth visiting one. I googled and found out that there are other Bitcoin conferences that will be on almost the same period as Bitcoin 2014.
It depends, for me it would be since it wouldn't require me to travel far. But I'd also like to attend some smaller meetups first to meet some of the people in the community.