Bitcoin is not a biggest bubble in human history , this because as now bitcoin has continue to gather more investors to invest in bitcoin ,if it is really a bubble ,then it will not survive until this time , but it is very popular nowadays and continue to be known all over the world.
What you say is not convincing enough. As far as my personal thought bitcoin is not bubble because people will trade and exchange currency worldwide without having to go through the bank. This makes people believe and use bitcoin.