It's a 2 Bedroom, Not a 3 Bedroom
I have a house listed for rent.
It has 2 bedrooms on the upper level and a full bath.
The first floor has a living room and an eat-in kitchen.
The basement is finished on one side and has the furnace, water heater, washer, dryer, and a sump pump on the other side.
People come to look at the house and immediately start to look at the basement as a third bedroom.
If someone needed to get out of the basement in an emergency situation, the windows would not be an option. They are too high up to easily get to them, they are too small to get out of them, and they have glass block, which makes it impossible to get out without taking great pains to burst through them, which would probably result in injury.
There is a back door, which could possibly act as an escape route in lieu of the windows, however it is on the other side of the room with the utilities, which could be a potential danger spot in an emergency situation.
There is no door to the finished room itself, where people would like to have the bedroom, unless they consider the door at the top of the steps as the door for the room, which would mean that the entire basement, furnace and all, would be considered to be the bedroom.
There is no closet, unless one were to consider the area under the stairway to be the closet, however it is not closed off.
In many areas, a window for egress, a door to close off the room, and a closet with a door are required for a room to be called a bedroom.
In addition to these three items which are required and which it does not have, one might consider how a typical below grade room tends to have a higher humidity than other parts of the house, which is not good for a person's breathing, although a dehumidifier could be used.
And, it would be quite inconvenient to be in a bedroom on the lower level when the bathroom is two levels up on the upper level.
In spite of these concerns, many people insist on jamming more people into a house than the house is designed to hold.
Their motivation is probably related to price. They want a 3 bedroom house for a 2 bedroom price.