I have been using similar flip-flops (with studs) for many years (maybe over 20). Personally, I am a big fan of them compared to any others.
However, I would describe them as massage flip-flops that help relieve the feet after many hours of standing or walking. And in this, they are very good. That is, to wear them at home for 1-5 hours. However, they are not suitable for prolonged use. That is, you can't wear them all day, go out on the street for errands or for a walk. They are also not for fast walking. Your feet will be on fire... If you want them for all-day use, then get something else.
I deduct one star because the silicone surface on which the studs are placed dries out after 1-2 years and the studs start to break. This is given that at least on my part, their use was light (I use shoes in my daily life, even at the beach).

It's not just for massage. If you want to train your legs to walk in heels, it's the best choice.

Obviously, flip flops are not for the beach, for the sea, as they hardened so much, where the "nails" that are supposed to give you a foot massage, are not only uncomfortable but also ONLY painful...this happened from the first month.... I do not recommend buying them, for use near salty water....It's like stepping on sharp nails!

P.S. After 2 years where they stayed in the closet, I found out that from size 44 they shrunk to size 39!!! Avoid buying them, they are not worth not even 1€!