I use my mini 6th gen as mainly as my digital notebook for work and it excels at that purpose. Being able to search my handwritten notes as if they were typed text is a revolution for me. The iPad also gives me easy access to my work email and apps while I am in meetings without me having to haul around the brick of a laptop they gave me. At home I use my iPad for web surfing, ebook reading, FaceTiming with family, and light texting and emailing.
My MacBook is for photo editing, graphic design, and anything that requires multitasking or longer typing. I’ve tried the iPad Pro route and, for me at least, hooking up a keyboard to an iPad pretty much defeats the purpose. At that point I’d rather have my MacBook. iPadOS can do pretty much everything macOS can. But it isn’t nearly as efficient at it. That’s also why I chose the mini. It can be held in tablet mode comfortably pretty much forever.