IVF: Fresh or pgs testing

Starting the IVF process! We had planned to do genetic testing. The nurse just told me that doctor recommends one fresh transfer and then the PGS testing on all the others. Why would he recommend this you think? Anyone have success with fresh or non tested embryos? I’m just nervous for it not implanting if we don’t test and I guess just in general. Especially since he recommends it for the others.

I am 35 years old, .4AMH. Husband 1% morphology.

Edit to add that it would be ICSI IVF in case that makes a difference?

Thank you SO much In advance!!!