Lousy video.
Takes 6 minutes of waffling to fail to explain why you don't want the isolated outlet to have any earth connection, then starts discussing the pitfalls of trying to 'float' a scope with it. At 8:30 he lights a bulb between mains Live and the scope probe ground clip, proving that he doesn't care enough for his own safety to have a RCD (ELCB) on his bench supply circuit. He then manages to float his scope at 11:45 using an old USA 2pin socket to 3 pin plug adapter with a flying ground wire going nowhere, and proceeds to make his whole scope live on a bench filled with other presumably earthed test equipment via the scope probe ground clip, while holding it.
In any workplace I've been in, he'd be on administrative leave while the company safety officer reviews his persistent failure to follow safe working practices.