That compound in particular is used to help replace a C-OH bond with a C-CN bond. It may seem like a weird chemical but it's very commonly used in organic synthesis.
> Why wouldn't the same but with a more typical fully-carbon backbone work?
Because a fully carbon backbone would not be as reactive and would not attach/detach from the intermediate as needed
> Why wouldn't the same but with a more typical fully-carbon backbone work?
Because a fully carbon backbone would not be as reactive and would not attach/detach from the intermediate as needed