[x] For session saving it already kinda is, as SimApp save/load deal with compression in the outermost call frame, after/before calling the actual save/load methods that don't need to care.
[ ] But it should be even more generic, so that it can be used for any other save/load tasks: the in/out stream itself (which load/save get as a parameter) should do the compression/decompression!
[ ] And even more generally: there should be a simple way to nest/wrap data streams into any number of encoding/decoding layers! (So e.g. the raw data coming from the model would go through some encoder, like TOML, JSON, whatever, which can go through (de)compression, and the whole thing can also be redirected to whatever storage or transport mechanism etc...
See: #290, #413, #366