The extra space makes the bathroom accessible for people in wheelchair. The bar and the chair in the shower make taking shower easier. It is also compact so it save efforts to get to the area people want to go.
If there is someone at home you know who has special needs, is sick or aged, for them Stair chairs and lifts would be heavenly to have around. Walking or moving about for them would be very strenuous and as they age, safety and security while moving around would be a herculean task to achieve and keep in mind.