How respectable is the CM title? I know a man who has the CM title and his wife is WGM. They wrote a book together and on the cover her name is given with the WGM title but his name is left without his CM title. I asked him about this and he insists that he is rather embarrassed by the low title.
I am wondering if it is advisable to put his title on the book cover. Will it confer respect or rather discourage readers? The readers are supposed to be beginners or amateurs or even chess enthusiast that do not really play chess.
Any answers should focus on how the title is perceived by potential buyers of the book, and not on the technical details of obtaining the CM title.
There are, of course, some players who have been given the title in perfectly "respectable" circumstances like reaching a certain rating or reaching 50% in an Olympiad. However, try this. Go to the FIDE rating website and do an advanced search for titled players sorted by rating ascending.

The first 7 players in the list are WCM with ratings between 1032 and 1143. The next is a WFM with a rating of 1154! Which kind of throws doubt on the WFM title too. Then the first CM with a rating of 1161. Ignoring the WCMs for the moment and just looking for CMs we see that the next ones come in at 1204, 1247, 1282, 1298.

What we also see with these very low rated CMs and WCMs is that they are very young, some as young as 7 years old. And therein lies a clue. Another way to get the WCM and CM titles is by finishing in places 1 through 3 in world and continental championships in age groups going down as far as under 7.

These titles are titles for life so if they give up altogether or just play a few games a year and stop improving they will always have their titles. 

You judge if giving out titles to players with sub 1200 ratings devalues those titles or not.