Marcus,
I'm a relative newbie here and wondered about their utility too. There are differing opinions about whether they really benefit our engines (one would think if they were important they would be OEM - but then again it is something else to check so it doesn't get full - that's very bad), but I concluded it was worth installing one and did so immediately after getting the car home. No one has said it will adversely affected our warranties, which is important.
A long time gear head buddy of mine with a sense of humor pointed out the real value in having one. With your hood up at the weekly "cruise in" night at your favorite Mexican restaurant (we love ours) when an interested person sees it and says, "What's that thing do?", you can tilt your head casually in the direction of your oil catch can and say, "That? That's my oil catch can. It adds 37 horsepower by preventing blow-by contaminants from the Positive Crankcase Ventilation system from reentering the intake manifold (or, better yet, the SUPERCHARGER!). Yep, best investment yet I've made in my Challenger!"
This will elicit either admiring smiles from the agog with wonder crowd of onlookers - maybe even some gasps of amazement - or - someone (say...hmmm...just about anyone who posts here!) in the back of the crowd will yell, "That's total BS!"
And then, a likely outcome amongst friendly gear heads, a spirited argument will ensue about oil catch cans and all sorts of modifications and how they affect horsepower and handling. And that right there is worth the money to buy a catch can!
But, you DO have to admit you were just kidding at some point!
Best,
Finface