Balaton,
Your question is a good sensible and one and just to help your understanding when managing a New B200 for a few years I always did the run up checks and allowed the engines to idle for 1 min before shutting down as per the flight manual. I used to get slightly better fuel burn than other aircraft I was aware of. Also someone I knew never did the checks in the KA he managed and had to have a full overhaul on one engine before the mid life hotsection was due due to bearing wear.
In addition doing the checks effectively changes the oil in the propeller control mechanism which means the 'cold' oil has been flushed through with warm oil before the takeoff run which would otherwise be the first time the pitch change mechanism is used on the trip thus possibly reducing long term wear and thermal shock.
I also never selected reverse below 60kts which was the unofficial advice of my FS instructor/Beechcraft and P&W rep. My propellers remained in good condition. Although I did use the full flight envelope of the engine whist some people do advise keeping the temp below 700 in flight.
Overall I believe in doing the checks, never reversing the aircraft to park and allowing the engines to run down before shutdown whist using the full flight envelope.
I hope this is a useful view for you,
MM