Is it possible to pour a concrete floor without reinforcement?

There is an old wooden barn next to my house that I am currently renovating. Now I have a question about the flooring.

The first option is a boardwalk floor, which I could lay myself or with the help of my dad (a retired carpenter).But the room is for parties, and a wood floor is not ideal. A friend I know (a screed master) advised me to use a concrete floor, which of course looks good. A screed is much more expensive than a polished concrete floor, which doesn't need to be polished as long because of the high cost of sanding. The current floor is also a very rough concrete floor. I would put 3 cm of insulation on it and then 8 cm of concrete fill.

Do I need reinforcement there as well? The floor doesn't have to support any weight other than the weight of interior finishes such as walls, etc. It's really just a floor. What else would be a practical and cost-effective alternative to a concrete floor?