IMO, I can't see the problem with anything DL is doing. The reality is you are flying in a confined, metal tube. It takes only one person to put the entire aircraft at risk. The more times F/A's interact with passengers, they are not only risking themselves, but they also can become carriers of COVID-19 to other passengers. Once up in the air, your options of "distancing" may become limited, so the less interaction, the better.
Also, DL is parking up to 600 aircraft...I think that says enough about the financial stress they are under. For two upcoming flights, I can now buy first class seats for less than what I paid for main cabin.