Is it common to have a relationship with your baby daddy's parents for the sake of your child despite your ex not being in the picture at all?

Hi, so I am a single-mom to a 3 y/o daughter. My baby daddy is a guy from New Zealand, we dated for a while back when he was working here in the States on a temporary visa.

I have no relationship with my ex, he's not involved in our daughter's life, he's made it clear he doesn't ever want to "settle down" or be a dad and

However, despite my ex not being involved in my daughter's life, my daughter is also the only grand child of his parents, so my ex's parents did reach out to me independently of him as they did want to have a relationship with my daughter (their granddaughter). They seemed like genuinely nice people so I agreed.

In 2023, they flew over to NYC to spend time with my daughter and later this year, two of us are flying over to NZ so she can spend time with them.

I actually have a good relationship with my ex's parents and send them regular updates about her.

That said, is it normal or healthy to have a relationship with your ex's parents for the sake of your child having a relationship with her grandparents?