Personal outlays include consumer purchases of durable and nondurable goods, and services. The income and outlays data are another handy way to gauge the strength of the economy and where it is headed.
Spending greases the wheels of the economy and keeps it growing.
Savings are often invested in the financial markets and can drive up the prices of stocks and bonds. Even if savings simply go into a bank account, part of those funds are typically used by the bank for lending and therefore contribute to economic activity. Needless to say, that's a big advantage for investors.