I see speakers at meetings large and small referring to notes on their phone instead of using paper or index cards during their presentations. It makes perfect sense: by using their phone, a speaker can edit until the last minute and doesn’t have to worry about bringing extra materials. 
There’s only one problem: it’s a bad look. Because we've been conditioned to associate smartphones with distraction.
It doesn’t matter that we realize the speaker isn’t actually distracted in that moment. Every time they look down at their phone, some part of us – consciously or not – feels like maybe they aren't fully present.
The solution? Keep your phone in your pocket (ringer off please). Print or write your notes. It may be a bit more work for you, but your audience will feel like they've got your full attention instead of wondering if you’re checking Instagram.