Yes, I work with requirements etc... That utilize this type of numbering
They are usually requirements documentation, not always called Use Cases.
This specific term is used to describe an artifact in RUP (rational unified
process). If you have a client currently utilizing this development process
for applications you will quickly find that they do not account for User
Experience or Interface. You will need to figure out how and where to Insert
your own milestones into their Inception & elaboration phases.