Most skepticism comes from rich people being able to use their wealth to certify or make a "convincing" fake of an emotional support animal (usually poorly trained) that they don't actually need. But someone with a phobic or anxiety disorder would absolutely benefit from having a way to redirect their reactions to stress-inducing stimuli in a way that doesn't make the situation worse.

I think the ideal is to have a support person, but in our alienated society, an animal trained to watch for and respond to stress reactions is a close second.