I believe the absurd things are:
- the idea (i.e. storing a database in a database)
- the fact that the resulting storage is faster than vanilla indexed db.
The repo's readme is a bit misleading and it does make it look like a mad scientist experiment but you can read more about it here (really interesting stuff): https://jlongster.com/future-sql-web
Obviously this project is still young, but I find it convincing (disclaimer: I don't use it yet).