I'm confused how you say it burns off, then you say it's gonna have to be cleaned??
We're talking about two different things.
-Blow-by will most likely be 100% burned off in the combustion cycle (unless you run a catch can that works to intercept it).
-Carbon Buildup cannot be solved by witchcraft, meth, catch cans or the such. Time and time again I've seen a new community that hasn't dealt with direct injection engines try all sorts of stuff to combat carbon build-up like Water/meth, catch cans, seafoam, voodoo, but when people pull off the intake manifold or use a borescope, it seems like a crap shoot.
To me, and obviously every single OEM car manufacturer has found it to not be worth it to run a catch can. Do they help in concept? Sure. Does throwing away a single gum wrapper that's in your pocket before race help in concept? Sure. But the benefits are so small they are basically null. Just my opinion.