Obtaining a helicopter pilot license entitles you to perform the duties of a pilot on that type of helicopter on which the exam was held for the license. If you want to sit behind the steers of another machine in the role of pilot-in-command you must undergo a brief training on this particular type regardless of the type of license held. Type of license is however important for performing flights at night, because with professional license you are not required to have an entry of VFR night as in the case of a private pilot license for which you have to undergo a separate night VFR training. Permission to perform instrument flight in IMC (Instrument Meteorological Conditions), that is below VMC (visual meteorological conditions) or VFR or VFR minimums spec. also requires an entry in the license regardless of its type. Ratings in a helicopter pilot license could also affect other kinds of acting as a pilot, for example instructor rating. Detailed information on the various ratings and circumstances of their achievement and sustain you can advise with us, the Office of Civil Aviation Authority or read a document called Part-FCL, which is linked below.
COMMISSION REGULATION (EU) No 1178/2011 of 3 November 2011. laying down technical requirements and administrative procedures related to civil aviation aircrew pursuant to Regulation of the European Parliament and Council Regulation (EC) No 216/2008