But the software already has multiple database systems built in. There's not exactly overhead to use what plumbing is already there, instead of writing to disk.
Firefox is absolutely abysmal at not corrupting its JSON stores, too. I've had it crash and lose tabs so many times. Perhaps moving back to SQLite wouldn't be a bad idea.
I had to recover somebody's bookmarks for them recently after it decided to destroy the main copy.
In an ideal world, software with 100 million users would be optimised for energy usage. It all adds up. This does pale in comparison to everything else, though.