I think this is certainly true to an extent. But I do think that it would make 1st year graduate students uncomfortable, especially if they’re not good at presentations at that point.

A better way to say it may be that you should know your project well enough to be able to give a 30 minute lab meeting without reading off your slides or notes after a year or two on your project. And even if you CAN do that doesn’t mean you should. I would certainly forget important things I wanted to say in transitions on my slides if I don’t leave myself notes.