Basements in the US are really nice. As other have said, they are typically really big (usually the entire foot print of the house above), isolated and sometimes have their own entrances.
My parents moved my sister into the basement when she grew up because it was basically an apartment. It was a lot bigger than her bedroom, and offered her the chance to accumulate some furniture and stuff that she would need when she moved out.
My parents moved my sister into the basement when she grew up because it was basically an apartment. It was a lot bigger than her bedroom, and offered her the chance to accumulate some furniture and stuff that she would need when she moved out.