Expect a massive round of landing bans for Icelandair across its route network. As far as I am aware, operating a passenger flight without cabin crew is illegal anywhere in the world. And for a good reason. While pilots are trained how to operate the doors (and have to open and close them for real on some ferry flights without cabin crew), the functions of the cabin crew aren't limited to the doors and the trolley service. What if there's a cabin or lavatory fire? What if a passenger becomes unwell or disruptive? What if an actual in-flight emergency happens? The pilots will have plenty on their plate and there's no chance they will be able to also prepare and possibly evacuate the cabin.
The only way this might work is if the idea is to use pilots who are not flying in the cockpit for the time being as cabin crew (after appropriate training). But even then, are there going to be enough pilots for that, given that the normal crew ratio is at least 2-2,5 cabin crew per pilot? And how long will training and checking them take?
Loads of unanswered questions. Hopefully this will not become the final nail in the coffin of an otherwise good airline.