In my opinion the oil catch can is used to catch the oil gases that are rerouted from the engine to the intake (to get burned). That causes the intake itself to get soaked with oil residues which decreases airflow. Additionally the oil in the intake air lowers the octane of the fuel - the ecu compensates that by changing the timing accordingly - so you may loose a few hp (probably only 2 or 3 but everything helps right? ).
The solution is to use a little filter instead of the rerouting lines or (which is better for the environment and the cleaning of you engine bay) use a catch can.
In short: I haven't heard that you need a catch can if you have a higher compresson. And you wont gain any noticable hp with a catch can but you keep your intake clean and you use the full potential of high octane fuel.