Not trying to debate. Just my observation……… in a multi port injected engine….. no benefits what so ever, since all the intake goes through the valves. The detergent in today’s gasoline’s keep the intake tract clean. The small amount of blow by gets recycled and burned.
a direct injection intake system only flows air into the cylinder Through the manifold. The injectors feed the chamber fuel. The small amount of blow by goes into the intake manifold, into the air stream and goes over its intake valve. Some burns off in the cylinder, some stays on the back of the intake valve and collects over time on the back side of the valve in the form of carbon build up. It WILL eventually need to be cleaned via chemical cleaning(not the best method) or a blasting. That process is expensive unless you know how to do it yourself and have the equipment to do it. The can collects the blow by that goes through the crank case vent valve. The can maintenance is much more simple than a walnut blasting. On my 17 WRX I emptied the cans every other oil change. Very little came out, but that was oil/water not getting to cover the backsides of my intake valves. I was able to get a scope in to check out the intake valves. There was very little carbon collected on the valves. I always use the oil weight called for. Synthetic, dextros low volatility oil (Enos), and it is changed every 4,000 miles along with a factory, NAPA gold or Wix filter(I do the same for my 21 2.5 liter Crosstrek, in fact it has 5,500 miles on it and the oil has been changed three times. next change will be at 9,000 miles.) I did DRIVE my WRX, shifts at 6,000 rpm, and cruised at 4,500 - 5,500 rpm. My Crosstrek is driven mostly in Manual/sport mode with shifts at 5,500 rpm and cruise at 2,500 rpm, so it gets driven harder than most I think. I will scope the intake valves at 10,000 miles and see how effective the can is. There cannot be any harm in running the can.
you have your opinion, I have mine that is all….🤷🏼♂️