My take on it is that the catch can will catch some oil. But over the course of 1500 miles and what appears to be 3 teaspoons of oil - that is 1 drop of oil every 5 miles. Literally. Imagine those guys who catch that much over the life of an oil change... you didn’t catch enough oil to even taste in a glass of water.
But, I get it, I ran one on my TT Jeep SRT8... just don’t see the need, even after seeing the results.