As usual it depends on what popular should mean, which usage area is ment to be used and what region of the world we are talking about.
The X-07 is a typical member of the A4/letter sized portable/laptop computers. THe most prominent family here are the Kyotronic 85 family (Kyotronic 85, NEC 8201/8300, Olivetti M10, Tandy M100/M102) as well as the Epson HX-20 and Casio's FP200. Albeit a late comer to that market.
AFAIK it got most use in Japan and some parts of Asia, much less in Europe, and comparable little in the US. Being quite late (1985, *1) the market was already quite saturated with other models - which in addition often offered larger screens and a greater software selection to the user. In addition, 1984/5 already brought the next generation, like the Tandy 200, and the market was moving toward units more like today's laptops (80 character per line displays, x86 CPU, etc.).
Canon tried to position it as low end device for people who would not like to afford the 'bigger' ones and got some success at the low end/hobbyist market.
Judgeing form how often french language sites come up when searching for the X-07, it might have had a good sale in France or French speaking countries in general.
*1 - 1985 in Europe (1984 in Japan). That's three years after the HX-20 (1982) and two years after the various Kyotronics (1983).