Home Assistant OS but it's container

Dears, I’m very new here and on Home Assistant. Today I installer HA os on my NUC following the official guide. I flashed the internal ssd with balena etcher with my desktop pc, I started my NUC and I reached home assistant from my browser.
It’s everything ok but in system information I see “Home assistant container” under “type of installation”.
How is it possible?

Thanks you so much

Ok… rebooting it’s now OS…