Nom…did you learn the gemara you quoted? The talmid chacham looked in shomayim at the throne of rebbe chiya, after being told that he could look at any of the other talmidei chachamim besides for rebbe chiyah. He did it anyway and got sick. He was chutzpahdik on his level, and asked rebbe chiyah for mechila for the affront.
Or did you just google “talmudic talk with dead” and quoted it without learning the context?
And here we go again – the difference between living and dead people is a pasuk in chumash.
It’s also logical; when a person’s alive, it’s like using any other physical thing for hishtadlus; a medicine, a car, etc…but when a person is dead, what can they for you(besides talk to Hashem for you)?
It shows that he believes in the power of something besides Hashem.