This paper reports on UK primary school teachers' and children's app developers' views about the potential of using personalized digital resources to promote young children's reading and play with 'smart toys'. Many existing digital resources are 'personalised', that is, the content of a story or game is tailored to an individual child, and the content is adjusted to the needs and preferences of a specific user (either by an adult, such as a parent, or through algorithmic calculation by digital software). In this study, we focused on the role of digital personalization in children's play with smart toys and in early reading with personalized books. Focus group interviews were conducted with 10 primary school teachers and 14 book and digital industry professionals, and the resultant audio-recordings were analysed using inductive thematic analysis. A dominant theme was participants' association of digital personalization with the potential both to enhance and to jeopardize children's and adults' agency. Overall, the convergence of the digital and personalized aspects in some books and toys constituted a source of concern, with different views offered by the teachers and designers.