I think it would be better than a regular keypad in terms of response rate as the scanning is limited to a single pin and then lookups.
What do you mean by response rate? Do you mean the number of keypresses per second you can read? In my implementation is was quite the opposite, the response rate was very slow because I had to wait the reading from analog input to stabilise, i,e., it took long time before the voltage rose after I pressed a key.
What resistor values did you use?