It's not real Amrit, from what I understand. The motivation behind it may vary from family to family. Some may see it as a sentimental gesture, a way to initiate their newborn into Sikhi, or a precautionary measure that would allow the parents to share utensils with their newborn without fear of it being "jhootah".
I strongly disagree with the latter motivation. How could something that comes from your own body be considered jhootah? It is a part of you.
Personally, I'm not a fan of ceremonies. It makes me think of the janeau saakhi of Guru Nanak. The naming ceremony, Amrit ceremony, marriage ceremony and death ceremony are more than enough, in my opinion.
But that's just me. What are your thoughts Ishna ji?
Sikhi is a very interesting concept which gives the person the tools to evolve with time.
Baptism in other religions is done some days after birth. It is a big thing in the Catholic side of Christianity. However, the Protestant took its thunder away with a new concept called 'Born Again Christian' where one is baptised at any age. Bluntly speaking, it is a ploy of guilt concocted by the Protestants.
In Hinduism, the ritual is 'Mundan' where they shave off the baby's head no matter the gender.
Khandei de Pahul is an optional thing for a Sikh as it was the last thing created by our 10th Guru when Sikhi had already been thriving for a couple of centuries. This is a very responsible commitment for the one who is ready and 'getting ready' for this affair is very subjective.
But we all know a baby has no idea about it. Hence Kirpan da Amrit becomes merely a dogmatic ritual which has nothing to do with Sikhi per se.