I think it's a gamble to do big-budget Space Opera TV shows. I accustom it to the fact that if the Show Devs make the show, and then it completely crashes in the viewing department, then they end up losing money: even it some people still watch it.
Ya know we're not 343i right? I know dern well I'll still thank them for doing the MCC for us though.
Anyway welcome back to the community TuNaG0TL0sT!
It might be like that due to these reasons:
1: If the Sword is situated in a fixed position then people viewing the Sword from the sides might have trouble making it out from the background, so the turning Hologram makes sure it's clear from all viewing angles.
2: Since it's a Hologram (from what we can see) it can be determined that you will be able to walk through it unlike a regular Sword where it's a physical object. That way people who don't want the Sword can still get on the platform and move freely through the Hologram.
3: In the actual H5G First Look Trailer (not the one you posted) there's a view of that destroyed map: specifically the frame where it shows a Fan Blade on the ceiling. Below that you can see another Hologram similar to the Sword Hologram in the trailer. Maybe Power Weapons get Holograms?