I believe that the families of the men had the choice of whether or not they wanted a CWGC stone.
I'm only talking about family memorials, not CWG ones, so I'd agree with you there, but these are all standardised to an extent anyway.
I've found hundreds of servicemen/women in local cemeteries across Stirlingshire who although are listed on CWGC or BWMP , are not listed as having a memorial other than the general memorial plaques in France, Belgium etc.
The CWGC stones are obviously much easier to find when trawling through graveyards or cemeteries but personally, I think that family memorials bring a wee bit more perspective to these brave souls - rather than just a name, rank and service number. I would say, in general, only about 10%-15% of the men I've found have CWGC stones.
I would imagine that eventually all the information from family memorials will be added to both the CWGC and the BWMP site as it's collated and double checked. I know a huge percentage of these won't be buried in these actual lairs but it's nice to see their names in amongst the rest of their family.
Anne