[dwattttt]

The optimisation the parent is referring to is development time/effort; if the alternative to dumping a structure to a file is to hand roll your serialiser/deserialiser, that's a slower & probably more error prone approach (depending on the context).

[skybrian]

The article makes an argument that the hand-rolled solution is less buggy, if you approach it the right way.

For complicated data structures, it's probably best to use a library that serializes to a common standard. (For example, protocol buffers or JSON.)

But I think the article assumes you don't get to choose the protocol, so it probably has to be hand-written by someone.