The process of transfer printing is (mainly) used for non-flat surfaces, if I understand the description by Guy Massé (my quote above) correctly: the first printing stage is onto some substrate (like paper) - and then the image is "transferred" like a decal.
Yes - Frank - if a b/w print is handcoloured, the dots from the printing will remain - BUT ... I'm sure, if someone during the mid 1970ies (Mosser paperweights) would print something, which should be coloured in the end, he would do a colour print, not b/w and colour it by hand afterwards (unless the aim was to imitate an old procedure for some reason). At least in Germany/Switzerland the last handcoloured postcards were produced during the first few years after WWII.