But why is loneliness a problem? Because evolution; being apart from the tribe was not a good survival strategy so we have developed an intuitive "feel bad when cut off" mechanism. Same with fear of ostracism; being cast out from the tribe was a death sentence. You can to a very limited extent "hack" it - why people carry around photos of loved ones in their wallets and look at them to trigger the recognition response - but a chatbot that could operate at that level would be indistinguishable from a sentient being in its own right, in which case why not make real friends with it?
Because with bot you can just shut them down when they don't behave like you expected or when you dont need them.
I don't think that knowing you can do this and successfully fooling your internal anti-loneliness mechanisms are compatible. You simply won't get the full range of emotional stimuli.