This article suggests that the type of Internet-enabled device should not be prioritised when conceptualizing diagnostic categories of addictive online behaviours. The diagnostic distinction between "predominantly mobile" and "predominantly non-mobile" forms of Internet use disorders (IUD) is not empirically based, may not be clinically useful and may lead to "diagnostic inflation." Problems with the concepts of smartphone use disorder and IUD on which the proposed distinction is largely based call for their re-examination. Future proposals for the taxonomy of addictive behaviours may not need to be based on online/offline and mobile/non-mobile dichotomies.