Irish Passport Express Service--checklist in details plz

[adublin]

Its about how to get Irish Passport through "an post Irish Passport Express Service" after naturalization. Now in this link: https://www.dfa.ie/passport
talking about new checklist:
1. form ( garda verified in certain section)
2. original non-irish passport
3. 4 copies photo (2 of them garda verified)
4. proof of address
5. photocopy of PSC card
It also says in that link- PSC card photocopy is sufficient for Photo Identification requirement.
So the confusion is, whats the need to send "original non-irish passport" ? They will send it back or make it unusable or may be destroy it?
OR is it really required anymore for person sending PSC copy should also send "original non-irish passport" ?
People who got naturalized in April 2016 and used "an post Irish Passport Express Service" with PSC card copy may/should know the answer.

Can anyone reply to clear the confusions here please ..?

Thanks & May God Almighty bless us all.

[noajthan]

Its about how to get Irish Passport through "an post Irish Passport Express Service" after naturalization. Now in this link: https://www.dfa.ie/passport
talking about new checklist:
1. form ( garda verified in certain section)
2. original non-irish passport
...
So the confusion is, whats the need to send "original non-irish passport" ? They will send it back or make it unusable or may be destroy it?
OR is it really required anymore for person sending PSC copy should also send "original non-irish passport" ?
People who got naturalized in April 2016 and used "an post Irish Passport Express Service" with PSC card copy may/should know the answer.

Can anyone reply to clear the confusions here please ..?

Thanks & May God Almighty bless us all.

Its likely to be to check what other identities the applicant holds in other countries.
The authorities cannot withhold or cancel another country's passport.