However, the smug "write-only database meme" is getting a bit old. Cryptocurrencies, and even other crypto-payment systems (e.g. chaumian cash) obviously have different characteristics than centralized money. Come to think of it, you could just mockingly describe any computer program that has structured data as a database.
Cryptocurrency has almost nothing to do with databases or storing data. At its core, cryptocurrency is a system of distributing signed transactions that uses hashcash as a sybil-resistance and (order) synchronisation mechanism.
Google spreadsheets need not apply. The whole point is that you don't require a single party to sign transactions. The problem that cryptocurrency deals with concerns co-operation between adversarial parties. Centralization leaves you hopping from platform to platform forever.