They are and they aren’t. You will get mixed opinions on this from ‘experts’.
Crocs are comfortable and easy to slip on and of, which is why they are so popular. They do have some arch support and a wide forefoot, which is good. However, for prolonged use that are not necessarily that comfortable and they do not have much support for the heel area.
You also have to grip the toes somewhat to help keep Crocs on your feet, so that can lead to some foot problems. Like wearing any new shoe for long periods of time, they can be painful as you are not used to wearing them and they may need time to get used to them.
Some Podiatrists like Crocs and some Podiatrists do not like Crocs. It is easy for a journalist is get a quote from a podiatrist either way if they were to write an article about Crocs being good for the feet or not.
The best advice is use them for short period and see how you go.