Someone searching for a service dog has usually pictured the outcome accurately: an animal that comes with them, that does something when the anxiety peaks, that makes a supermarket possible. That is a real and achievable thing, and it is trained work.
What they often have not pictured is the timeline. Getting a dog dependable enough to work amid the noise of a public place is a matter of many months at minimum, frequently far more, and a fair share never arrive however much is invested. That is not a reason to abandon the idea. It is a reason to know it before spending.
Meanwhile the thing being sold to them under that name is frequently an emotional support animal letter with a service dog vocabulary wrapped round it. The letter may be perfectly legitimate; the framing is not, because no letter of any kind produces a trained dog or public access.