Comment by SonOfLilit

When I said "allows you, if you're very careful and really know what you're doing, to write performant code that won't garble files", by "performant" I was alluding to direct overwrites. If you don't need direct overwrites (perhaps because your savefiles are tiny), then no problem. If you do, you should use SQLite or LMDB or something, unless you work at Oracle or somewhere else where your job is to compete with them.

The example I had in mind was Word, which gave up on direct overwrites and managing essentially their own filesystem-in-a-file in favor of zipped XML, which is really good enough when writing a three-page letter, but terrible when writing a book like my mother is. Had they used SQLite as a file format, we would've gotten orders-of-magnitude faster save on software billions of people use every day.