You won’t be able to pick a PAT, set up onboard account, upload your passports or security photos. You receive a QR code that’s like a boarding pass and they’ll ask you to show it 15 times before you board.
DCL embarkation has been horrible since the restart. I wouldn’t do anything to make it more difficult.
When we cruised in January they had people lining up outside by PAT. You know how Disney loves lines. This has been the process the 5 times we’ve sailed since the restart. Hopefully it’s changed.