ᐅ Basement staircase: closed off or open?

Hello everyone,

I’ve taken the step and bought a house built in 1970. Now there are some tasks to be done. I want to have a new staircase installed. Next to the staircase is the access to the basement. Currently, the basement is accessible through a door.
If it’s relevant, my basement is not built underground but at ground level. So the basement floor is level with the street, for example. The house does not have modern insulation or energy-efficient features—just typical 1970s standards.

I visited a stair builder today, and he suggested installing an open staircase.

Has anyone here had experience with this? Can you give me any advice or tips?

Regards,
armikxx

Are the basement rooms normally heated and used as living spaces, or are they just for storage?

I would definitely seal it. Otherwise, cold air will always rise from below, unless the temperature at the bottom is just as warm as at the top, which I doubt.

The basement has a radiator and is not intended as a living space. Laundry rooms and similar areas are located in the basement.