You in fact are misunderstanding the article, reading on an electronic device is included reading for pleasure - it is one of the three categories listed parenthetically as that.

Quote: The study focused on two activities: reading for pleasure (reading a book, newspaper, magazine, reading on electronic devices and listening to audiobooks) and reading with children.

From the linked actual journal article I thought this part should be limited to e-readers

> ATUS asked participants to recall all their activities over 24 h, beginning at 4 a.m. on the day prior to the interview and ending at 4 a.m. on the day of the interview (Figure 1). Activities were coded using a standard lexicon, verified by two coders. We focused on two reading outcomes: (1) daily reading for pleasure, classified by ATUS as reading for personal interest (e.g., reading a magazine/book/newspaper, listening to audiobooks, reading on a Kindle or other e-reader; Table S1); and (2) daily reading with children (e.g., reading to or with household or non-household children, listening to child read, helping child read; Table S1).