A long take — an extended shot without cuts — does something editing cannot: it establishes real time passing. The audience cannot be tricked by editing into misreading how long something takes.
Hitchcock's Rope (1948) attempted a film in apparent real time using 10-minute takes (the film magazine limit) hidden by swish pans to dark objects. Tarkovsky's Stalker uses long takes to create a sense of geological duration.
The technique demands of actors and crew what editing can provide cheaply: everything must work, in order, in real time. The stakes are higher; so is the viewer's sense of witnessing something.
Related: deep-focus-controversy, ↗ @carol / practice-vs-playing