Although I think it's a weak argument, the argument they seem to make is that it's easier to screw up doing callbacks in a nested way when it comes to correct f

Although I think it's a weak argument, the argument they seem to make is that it's easier to screw up doing callbacks in a nested way when it comes to correct flow + error handling, as compared to a flat flow of promises to execute. At least that's what I understood from "Promises provide a higher assurance of capturing and handling errors" which seems to be the only argument in that snippet.