Things that looks like slam dunks in theories are never such in practice. Weird bugs pop up from time to time; and believe me, they will!
It might be rare, you may only see it once or twice in a project; but when it happens, you’re gonna want to be ready, or people will question your ability to do your job.
Yes, however price is more important that all that. If your management knows it can save 20% on their cloud spending by running ARM they’ll run ARM and have you deal with those rare bugs.