PCV CONVERSION

For a low-rpm engine, that first type system will be fine.
The closed type offers two advantages;
1) it replaces the breather which has to be periodically cleaned with a different sealed oil separator, and a hose to the air cleaner, where it gets filtered air. and
2) the harder the engine works, the more blow-by gasses are created. There comes a point where your engine may be working harder than that system can keep up with, and some of the gasses will run backwards thru your system and puke dirty vapors plus oil all over the valve cover. The closed system will reroute clean excess vapors, mostly just dry gasses now, up the hose into the airhorn to join whatever other air is getting inhaled.

Another problem with the first system is, nobody remembers to periodically clean the breather, so it loads up with dirt, and collects liquid oil, the oil attracts the dirt, which then gets sucked into the engine.