The South Side Chicago apartment in which the Youngers live is cramped, over-crowded, and generally run-down. Under the circumstances, it's no surprise that Lena Younger, the family's matriarch, wants to use the money from her late husband's insurance policy to buy a nice house out in the suburbs.
The suburban idyll will be a status symbol for the Youngers, a sign that they'd gone up in the world. More than that, though, it would give them a place to breathe—a place with more space and privacy than their current accommodation.
The prospect of moving out of their crummy little apartment gives the Youngers something to aim for in life and a chance to fulfill a dream that remains out of reach for many in their situation. It opens up new horizons, giving them the opportunity to take their place in society.
Though the apartment in which they live may be cramped, the Youngers are still hugely ambitious for themselves, as can be seen in Walter's and Benetha's as well as Lena's wish to move out into the suburbs. What this shows us is that far from narrowing the Youngers' horizons, the place in which they live actually serves as a spur for self-betterment.