They're pretty explicitly saying that this isn't an entry-level database—which is perfectly OK. For example, in the docs it says that Cloud BigTable is not a go

They're pretty explicitly saying that this isn't an entry-level database—which is perfectly OK. For example, in the docs it says that Cloud BigTable is not a good solution for less than 1TB of data. If you're storing more than a terabyte of data and need the benefits that BigTable provides, you're probably already spending at least $1,500/month on your current database.