I mean, if you watch the tech demo clip and even more so if you watched the rest of that Unreal keynote, there's little reason for it to not look like that. They're using all the same tools to rig and construct the cinematic that they use to create gameplay.
Only reason to downgrade from that fidelity would be limitations of consoles or something and then they pass those limitations along to PC. UE 5.4 has a lot of optimizations that should reduce this need though, as demonstrated during this and other parts of the session.
The industry has absolutely earned the pessimism though, I get it.