Room treatments are really important for small and medium sized rooms due to the close reflections....but in a big room like this, look at how far away the speakers are from any boundaries....they aren't going to get the smearing and comb filtering that happens when you see speakers a few feet away from a boundary. All but the lowest bass frequencies are going to have the space to fully propagate so you can get even bass.
I agree hotel rooms at shows aren't good. The rooms are too narrow so the early sidewall reflections create a comb filter and throw off the response...that's why I think horns and dipoles have a big advantage at hotel room shows. Don't get me started on some of the rooms of YouTube reviewers.
I will say again the XLS-Encore was at a disadvantage due to the size of the room. It was not designed to play full range in a room this large. It would need to be high passed to a subwoofer.
