Very true, but most people do not yet no about scale-to-zero pay-for-what-you-use sql server clouds with a free tier like CockroachDB and neon. They think that you must pay $5 a month to run a sql server, which has been the case until very recently, so they go with no sql options to get the free tier.

Edit: actualy Spanner looks like another CockroachDB. You use sql to interact with it. In which case I can see many people who would want to use this with a free tier for hobby projects. ie. in between education and production development.