I would caution the use of your visual cards - part of the role of ethnographers and designers during research is to see beyond the limitations of what a research subject can show and/or tell us - we observe & listen but then we use our expertise to make judgement assumptions based on the context of the problem at hand - and your cards, while offering a different approach to explanation or choice, are still limiting (in this instance, limiting the users’ choices to the visuals you’ve placed in front of them - because they will always defer to a visual aid rather than search themselves for further explanation). Just my two cents.
The Henry Ford quote is a perfect example. Lee Iaccoca is credited with a similar quote regarding consumer research.