Many internal ACF functions are not documented.
The functions you mention are used internally to make fields used in blocks available to other ACF function like get_field() when rendering a block and really do not have any real use that can be leveraged for some other purpose.
There are a lot mentions of these functions and I don’t see any alternative.
For example accessing data of Gutenberg Blocks if you have the post:
https://portalzine.de/dev/php/advanced-custom-fields-get-gutenberg-blocks-data/
In the document that you provide the author is doing something outside of the norm and accessing the block data directly so he is calling these function in the same way that ACF calls these function. He is looping through the blocks on the page, calling the acf_setup_meta() function and then calling acf_get_fields() in order to store all the ACF fields for a specific post into an array that can be used later.
Exactly, thank you for reading the article in depth.
There are many cases where you have a post and need the data of the blocks and all I found use these functions or their predecessors.
https://gist.github.com/jenssogaard/54a1927ecf51c3238bd3eff1dac73114
As I said, there are a lot of internal functions that are not documented. What is documented is what 90% of users need.
