personally i think bitcoin is an assets,when ever bitcoin is a currency, but bitcoin currency is very strong currency so we can say bitcoin is a currency and big an asset.
As I said it is more of an asset then currency , there are more people investing in bitcoins rather then using it for transactions and no matter if it gets centralized or not the fact will always be same , as compared to gold which has been with us since ages and once was used as currency too but with due time it has been changed from a currency to asset as there are people who like to invest in them rather them use them for transactions.