The main purpose of the foundation is to hold the structure above it and keep it upright. In other words, the foundation carries the building that sits on top of it. A poorly constructed foundation can be dangerous to the occupants and the neighborhood. A properly-built foundation could sustain the wrath of a natural phenomenon at a much higher level and remain safe for the people inside it.
The foundation distribute the load of the structure over a large bearing area so as to bring intensity of loading within the safe bearing capacity of the soil lying underneath. A house which is just plonked down on bare earth is more likely to be cracked or damaged over time by natural forces. A properly-built foundation could sustain the wrath of a natural phenomenon at a much higher level and remain safe for the people inside it.
In a house construction, although it is a mere single-level or two-level structure, its structural integrity shouldn’t be sacrifice just because of the cost involved.