Example: Cash flow is not the same as profits/losses. If you buy a $1M CNC machine for $1M in cash, your profit is $0 but your cashflow is -$1M.
Example two: Expenditures are different from expenses. The date you agree to buy (and are legally contracted to buy) a $1M CNC machine may be different than the date that those funds leave your bank account. (And those dates may be different than the dates over which the $1M CNC machine depreciates and eventually breaks down.)
Issues like these two can cause a business to run out of cash, even when then business is making a legitimate profit. This is why an income statement detailing your profits & losses is not enough - you also need a cashflow statement.