The Lucee docs for structGet() are correct but cfdocs are not, and it may just be that the Lucee docs are incomplete. Lucee correctly specifies that structGet will return a struct at the specified path, but cfdocs (and ACF) indicate that you can use structGet() to drill down to a value. For instance, the Lucee docs example:
This works fine, but per cfdocs and ACF, you should be able to do:
...and get true. Lucee returns an empty struct, because there is no struct called sleep ... just a key.
Lucee's approach makes sense to me but it may be worthwhile to support the same usage that ACF does.