I was of this opinion until I moved in with my partner who had a bearded dragon. Reptiles move strangely, but this bearded dragon had been a classroom pet for the first few years of her life, and was surprisingly social. She'd make eye contact, gesture with her body, present her head to be gently pet around the bristles, and even flip over to be rubbed on the belly like a dog if she was not currently or just finished eating. Responsive with body language to some specific one or two syllable words like her name or the words for mealtime, and very aware of visual cues (like any of the objects she was handed a mealworm from, even just once).

I imagine a tarantula probably has some behaviors that would surprise me if it was conditioned as a pet and socialized, I know they have a fair number of ways aside from the bite to show displeasure or anxiety like flicking hairs and quickly shuffling away to show a defensive posture. I think it could be a fun experience and wouldn't turn my nose up at it instantly these days if the opportunity came along; animal cooperation is a small joy even when it's a bit foreign.