The stick response puts a slight delay in when the transmitter starts the move the control signal. I guess this is to simulate older transmitters that some fliers are used to. Futaba listens to F3A and F3C pilots when planning features for their transmitters.

"Hysteresis" is basically deadband upon stick movement. It is active at all stick ranges. You could, if you deisire (though why is a good question), set the sticks so that you have very visible movement before any control will move. This applies to the stick, and would be analogous to having "play" in the steering wheel of an automobile. You have to move the wheel a certain distance before any steering would take effect, and then have to move through the deadband to steer the other way.

These things may be developed from the habits of top Japanese model pilots. I do know that the hysteresis is used by F3A pilots to control collateral stick movement. For example, if you are performing a slow roll, and have to hold 1/2-stick movement, hysteresis prevents the transmitter from moving the servos when you make the inevitable small movements while you try to hold the 1/2-stick deflection. Other pilots will set a rate that allows them to slam the stick all the way to the physical stop and have the ailerons at the slow-roll setting. It depends upon style. However, if you set a rate, it's harder to adjust the roll rate to suit the judges when you discover that their "slow roll" is faster/slower than your "slow roll" and on, and on, and on.

All part of getting the transmitter set up so that it is part YOU! So many programming options get it customized to suit you, and you alone. Top-level, world-class competitive pilots will use every edge they can get, and these features are some of them.