David's Harp

Why is David's Harp on the back of Irish coins?
Why is David's Harp NOT on the back of any Middle Eastern, Muslim, or jewish coins?
Why would the Irish put symbols on their coins from foreign governments, religions, or societies?

1Sa 16:23 And it came to pass, when the [evil] spirit from God was upon Saul, that David took an harp, and played with his hand: so Saul was refreshed, and was well, and the evil spirit departed from him.

2Sa 6:5 And David and all the house of Israel played before the LORD on all manner of instruments made of fir wood, even on harps, and on psalteries, and on timbrels, and on cornets, and on cymbals.

1Ch 13:8 And David and all Israel played before God with all [their] might, and with singing, and with harps, and with psalteries, and with timbrels, and with cymbals, and with trumpets.

1Ch 15:16 And David spoke to the chief of the Levites to appoint their brethren to be the singers with instruments of music, psalteries and harps and cymbals, sounding, by lifting up the voice with joy.

1Ch 25:1 Moreover David and the captains of the host separated to the service of the sons of Asaph, and of Heman, and of Jeduthun, who should prophesy with harps, with psalteries, and with cymbals: and the number of the workmen according to their service was:

2Ch 29:25 And he set the Levites in the house of the LORD with cymbals, with psalteries, and with harps, according to the commandment of David, and of Gad the king's seer, and Nathan the prophet: for so was the commandment of the LORD by his prophets.