The always-wise Laurie Kaye has some useful memories which concur with mine. His take on the Supreme Court’s recent judgement about the NLA is useful reading. Lord Sumption should give it a squizz.
As I recall, the majority of the discussions around Article 5.1 concerned these kinds of temporary copies made by the Telcos’ networks and machines. True, the reference to “lawful use” pointed to other, “off the network” technical, temporary copies such as cached copies in a computer’s memory which were incidental to some other “lawful use” e.g. prior to a download. But this was not the central point and the notion of “lawful use” was seen in the context of technical copies which happened in the course of some other licensed activity.