There isn’t enough vacuum in the the inlet pipe to make that much of a performance gain on the motor by hooking the can this way, but yes done right and keeps the smog crap/blowby flowing out of the case. If you’ve got more than ~1-2hg of vacuum in the inlet pipe on a turbo motor then you’ve got filter restrictions. Even 2hg is pushing it. FWIW, ~2hg of vacuum collapses the non-wired aftermarket silicone inlet pipes with ease on the Subarus.
You’re talking about the big gains from running belt or crank driven vacuum pumps and air/oil separators at ~15hg+ and using low tension rings in the build. Yeah then you free up some good power there! 
Turbo motors benefit from gas ported pistons big time too.