I grew up in one of these households. My grandmother didn’t speak English so my dad mandated Hindi be spoken in the household.

I think it was a net positive in my life. I pick up phrases and sounds from new languages pretty easily. I didn’t do great in my English classes in HS but am a pretty good writer now.

From an assimilation pov, I think it’s pretty important to grow up speaking whatever language you do alongside English. I don’t have the data but I know ESL kids have a hard time in early schooling here in California.