I would guess they're only used to research fake meat. As in, to understand the chemicals and nutrients that make up actual meat and give meats their properties. An example I suppose would be to understand the chemicals and reactions involved when cooking meats e.g. how meat browns when cooked[0] and then synthesise these chemicals from plant matter[1].
[0]: https://en.wikipedia.org/wiki/Maillard_reaction
[1]: https://faq.impossiblefoods.com/hc/en-us/articles/3600189374...
Or does fake meat not use this material in its production? Maybe it is only used in researching fake meat?