Bio degradable packaging is not really suitable for composting yourself. Most of it takes a really long time to break down naturally or requires high composting temperatures that can be hard to achieve in a home compost pile. This is true even for basic stuff like cardboard and paper. You also need a lot of "green"[1] (high nitrogen) composting material to balance out cellulose from packaging.
The net result is that this is still an industrial process. Though probably less energy-intensive than recycling.
Source: we have a compost pile and it's not all sunshine and roses.
A lot of "biodegradable" will use a literal interpretation, in that it it degrades in nature. 500 years you say? But it still degrades...
Home compostable is really the only one that makes sense. Even industrial composting requires a high heat environment as the catalyst, so if something contaminates the batch and goes into general refuse then it will never break down.
if all fails, just leave an option for nature to do it for you