What, exactly, is an 'average' pet? A dog? A cat? A tarantula? A hamster? Or are you referring to behavior? If so, what is the 'average' of this? They can all be 'friendly' in their own way but show it VERY differently. 'Comforting'? I don't have companion animals to 'comfort' me so I don't know what you mean by that. But I can tell you that, for one thing, although lots and lots of people have birds nowadays, the greatest majority of them are not bird people and they have the parrot for their own benefit. Same as the greatest majority of dog owners, cat owners, etc. They have the animals for what the animals can give them... unconditional love for people who feel unloved, company for people who feel lonely, etc and then there is the status/show off aspect of it which is, unfortunately, what drives most people to keep a parrot.
True bird people simply love them for what they are. Whether it's a canary, flitting around in a cage and singing its little heart out or a parrot that is more like a little person than anything else but, in truth, beauty, song and/or brains are not the 'driving' force behind our keeping them - or, as you call it, the 'point'. The point is love and wanting to help them have as good a life as one can give them in captivity because they cannot be released to the wild. Canaries are a domesticated species that doesn't exist in the wild so they need humans to care for them. And pet parrots are damaged animals. We took them out of their natural habitat, tricked them into imprinting to people and kept under unnatural conditions that make them suffer every day of their lives. So, true bird lovers try to make it so their lives are not so terrible. That's why we keep them. Or, at least, that should be the only reason why we keep them but, like I said, most of them are not acquired or kept for the right reasons but out of sheer selfishness - a 100% human trait.