A Public Update is the exact same language independent file which is part of a CU. The only difference is that it is made available through Windows Update because it contains a security fix.
So, does it make sense to talk about CUs and PUs?
Because it is the same language independent file... and because TechNet only uses the term Public Update for all updates. It is up to you but in my opinion it makes sense:
- The word cumulative better matches its content, a monthly rollup update. You can skip it if you don’t need it.
- The word public better matches an update offered through Windows Update, which includes a security fix.