When I first started working on BoltHold (a simple querying and index engine that sits on top of BoltDB), Badger didn’t yet exist, and BoltDB was the clear leader of the pack for key-value, pure-go, embeddable databases.
Then Badger was released, and it was shown to be more than just a pure-go version of LSM-tree stores like RocksDB / LevelDB, it actually was faster than RocksDB. Much faster. I knew I wanted to build something with Badger in the future, and when an issue was opened to add Badger support to Bolthold, I jumped on it.