Draco honestly hadn't really thought about it as a big deal, he had just assumed that Harry had a muggle phone as well. It probably seemed weird that he of all people had one though, but it was purely for professional reasons. In Paris it was normal praxis to have a muggle phone as a healer, mostly for their muggleborn or halfblood patients. He had decided to keep the phone in London for the same purpose. "It's common for healers in Paris to have a muggle phone, so I decided to keep it when I got to London," he stated with a soft shrug. It's practical, mostly in regard to magical people, who made their daily business in muggle London.