I expect confusion and some anger all because of the lack of clarity US law is specific to the USA. Canada has a stricter definition. The one common area of confusion will be in the definition of a service animal as a dog. Because the airlines will use interchangeable terms, I expect that some passengers will be confused. More importantly, the legal definitions still allow for psychiatric care service dogs on US flights and a more limited form on Canadian flights.

US DOT has this definition; Under the Air Carrier Access Act (ACAA) a service animal means a dog, regardless of breed or type, that is individually trained to do work or perform tasks for the benefit of a qualified individual with a disability, including a physical, sensory, psychiatric, intellectual, or other mental disability. Animal species other than dogs, emotional support animals, comfort animals, companionship animals, and service animals in training are not service animals.

Canadian transportation Agency has this;
What is considered to be a service dog: The ATPDR define a service dog as a dog that has been individually trained by an organization or person specializing in service dog training; and performs a task to assist a person with a disability with a need related to their disability.
Tasks performed by service dogs and proof of training:Service dogs perform a variety of tasks to provide support in activities of daily living for a wide range of disabilities, including guiding persons who are blind; alerting persons who have hearing impairments to the presence of people or sounds, such as an alarm or telephone; pulling a wheelchair; recognizing specific changes that happen before a seizure and alerting a person; and providing assistance to a person with post traumatic stress disorder by providing a barrier against other people crowding too close to the person.

Ok, so we will be spared the presence of barnyard animals from Porky Pig to Pepe LePew, but we will still have people with their questionable purpose companion dogs

And away we go. That is your personal opinion.
One should not generalize. A person traveling on an airplane with a support animal may be a productive member of society because of that animal.
If a person is allergic to animals such that a medical crisis would occur if exposed to an animal dander or saliva proteins, then the person should not travel. The reason being that if that sensitive person was in proximity to a person covered with the material, that person would suffer the same reaction. Oddly enough, such an incident is never is reported, is it? And it is far more likely that such a sensitive person would be sitting in close proximity to a contaminated person than an animal.