Is it with the ecoboost engine? If yes, then it may help reduce carbon build-up on the intake valves. It will still need a carbon cleaning no matter what because some oil vapors do get the separator sometimes. If its not ecoboost, then don't worry about it because those other engines are port injection. The gasoline will clean the valves for you.

Note: check with your state's emissions laws first before installing one...it may be illegal.

I put one on my '18 and '19 GT's, but only on the passenger side. The driver's side is the clean side and unless you road course the car it is not necessary. 

The FRPP ones are nice but a pain to drain. I used the JLT can and found it super easy to clean.

The reason you need one: 

On a direct-injected car (your GT), the fuel is fired right into the engine and does not wash over the intake valves as it does with port-injection. This means that the fuel that would normally wash the valves and keep carbon build up down to a minimum is no longer there. With a catch can, you "catch" the oil that would otherwise just sit on those valves and coke up, creating a nasty build up over time. If you do not have a can, you will eventually have so much build up you'll need to pull the intake manifold and have it walnut-blasted clean, which is a very expensive process.

Long story short: For your car, it is a good idea. For cars running port injection, or direct and port injection, it is not necessary.