AC Input Voltage Sensing : Isolation ?

Retaw

Hi Wolfspeed Experts .

I'm interested in referance design for AC/DC Converters for an DC Fast Charging product and i come across 2 Referance design :

[1] https://www.wolfspeed.com/crd25ad12n-fmc/

[2] https://www.wolfspeed.com/crd-22ad12n/

I was comparaing the ac input voltage sensing design and couldn't help noticing the presence of an Isolated Amplifier in [2] and not in [1] :

My questions will be :

1. Why [1] doesn't use an isolated amplifier ?

2. Since adding an Isolated Amplifier will cost more, why it was implemented in [2] ?

Looking forwards for your response.

Thank you & have a nice one.