Short answer: yes, for the cat who treats dinner as a race. A slow feeder bowl puts ridges or a maze between your cat and the food, so a four-second meal becomes a two or three minute one. It does not change the food or the amount. It changes the pace.
What a slow feeder actually does
A slow feeder is an ordinary bowl with an obstacle course moulded into the base. Instead of an open dish your cat can bury its face in, the food sits in channels and around ridges. Your cat has to work the pieces out with its tongue and a paw, a few at a time. That is the whole mechanism. Nothing electronic, nothing that portions or times anything. The bowl just makes the food harder to reach, so eating takes longer.
Which cats it suits
The clearest fit is the cat who empties a normal bowl in seconds and then looks around for more. Slowing that cat down turns a gulped meal into a small activity. It also suits an indoor cat who does not get much of a puzzle in a day, since working at a maze is a mild bit of enrichment at a moment they are already interested.
If your vet has asked you to slow your cat's eating for a specific reason, follow their guidance on how and how much. We make the bowl, not the medical call, and we would not want you to read a product page as one.
Does it work with wet food, or only kibble?
Both, within reason. Kibble and chunky wet food sit in the ridges and take real effort to fish out. Very runny or pate-style wet food tends to slide into the channels and defeat the point, since the cat can just lap it up. If your cat is mostly on smooth wet food, a maze bowl will do less for you.
How to introduce one
Put it down alongside the usual bowl at first, with the food your cat already likes, so the only new thing is the shape. Most cats investigate within a day or two. A few decide the maze is beneath them and walk off, and if that is your cat, you have learned something about your cat.
What a slow feeder will not do
It will not change what is in the food, and it is not a health device. It is a bowl that makes dinner take longer. That is a genuinely useful thing for a fast eater and a bored indoor cat, and it is also the entire claim. Anyone promising more than "it slows eating down" is guessing.
Our version
The Gorogoro Bowl is our take: a low, wide dish with a ridged swirl maze in the base, in three soft colours. It is named after ごろごろ gorogoro, the sound a cat makes when things are going well. It is 23 cm across, stays put mid-enthusiasm, and rinses clean in seconds, which matters more than it sounds when you are doing it twice a day.