"C/S, looking, visual / nothing seen" =
clear, concise, unambiguous and an appropriate response to a nice ATC mate trying to keep 2 of you out of the same place at the same time.
If you see it - miss it.
If you don't see it -"nothing seen" will usually get further ATC info to get you a chance to see it / avoid it.
"Roger" is not particularly informative (even though it is in a pretty book).
Roger (I see it?)
Roger (I hear you?)
Roger (so why are you still flying towards it?)
KISS stay alive