It’s a little confusing but therapy animals, service animals, and emotional support animals (ESAs) are all totally separate things. Service or assistance animals are the ones you described that help blood sugar or panic attacks, guiding the blind, or whatever. They are specifically trained to perform specific tasks to mitigate a disability. And they DO NOT require any sort of certification or registration or anything. They are allowed anywhere. But are only allowed to be dogs or mini horses. ESAs are just pets with no special training and no public access rights but they are allowed on airplanes and pet free housing. They do require a letter from a doctor or psychiatrist, etc. for the housing I believe. But there’s a lot of scams online. They can be any animal I believe. Therapy animals help other people like they go to schools or nursing homes, etc. to visit with people and do require training and certification.