"why IO (input output) interfaces are needed for computers?"

besides
-to bridge differences between CPU and the IO devices
-to provide some means to assist I/O devices & CPU to operate asynchronously
-to regulate the differences in speed between the I/O devices and CPU
- to be able to interpret and transform different data format to and from the I/O device
-resolves differences so that as a middleman, it enables the CPU to interact with the I/O devices

wat else can it do? thanks