When you build highly distributed systems, making sure a value is properly transferred across different types of machine is actually not a trivial task because sender and receiver may encode values differently at the bit level (for example, because different endianess system is used). Erlang VM take care of this naturally, and the language offers built in functions to encode / decode binary representations that can be sent over basic transmission channels (like TCP / IP sockets).

If Erlang is not your cup of tea, look at htons() and nstoh() functions to have another example.

My trade is in real time distributed systems applied to the automatic control of trains. You wouldn't believe the number of times I have had to fix this issue in multiple codes, both new or legacy.

And my example is limited to individual values, not data structures. Think about how ugly things can turn if you have things like lists or dictionaries.

When you consider that Erlang adds on top of this built-in marshalling and demarshalling of data structure. As of today, I haven't found a more efficent environment to do this kind of stuff safely.

Probably referring to the external term format used in multi-node distributed message passing: http://erlang.org/doc/apps/erts/erl_ext_dist.html