Its less about how much land is being used and more about the accessibility of that land. By suburbia being spread out so much, transportation becomes more difficult to implement. Many suburbs are so far away from a simple groccery store that walking there is unreasonable at best. Being so spread out also means we need to spend more resources to provide services. Thats more miles of roadways, water pipes and electrical lines that need to be installed and maintained.

There are other important things to consider too besides just total land area like wildlife corridors, stormwater management, and access to nature as an amenity.