I presume at the time of Adams there were light meters around which gave you only the candles per square foot values, and you had to convert them in photographic values. It's the same measurement, if I get it right, expressed with a different unit of measure.
My Minolta spot meter F comes with a conversion table between EV at ISO 100, candles per square meter, and foot-lamberts. E.g. EV 14 is equivalent to 2300 cd/m^2 or 670 fL.
If you have to use a light meter, and you use it for photography purposes, then it's better to use one which gives you straight EV values, or maybe exposure "couples". I see no advantage in having a measure in another unit and then converting it to your purposes.