Hi,

> yes I know.
> But  just to keep some kind of uniformity, as the book seems to suggest.

no. the more widely used name is CJK.
see http://en.wikipedia.org/wiki/CJKV, it will redirect to CJK.
Unicode standard also classified the group as CJK.
(Version 5.1.0, page 409)

CJK uses the similar writing systems, all of them use Chinese Characters.
Modern Vietnamese do not include Chinese characters, it uses the Latin
writing system.
Only ancient Vietnamese includes Chinese characters, and that's why
some websites/books use CJKV.