I don't go by the thought process such as should I own 2 devices, each one has it's own purpose in my view, I'll explain further with my own use case:
My 27" iMac is my main desktop and I love it for the very big screen and it's form factor, (although the screen is outdated now since it's the 2012 model that I don't even think is retina) it's something I use for multiple purposes, sometimes I edit podcasts watch videos, play games and so on.
My iPad Pro 12.9" is what I use along with Apple Pencil to draw, write notes, watch Netflix, record podcasts and so on, it's a great iPad.
My MacBook Pro is now old (2011) and due an upgrade but I use it for writing, and taking with me to my friends when we collaborate and record our podcasts.
You see each device has multiple uses, don't get strung up on what other people think is normal because their normal use case may be different from yours, if your happy using an iPad and a MacBook then that's cool.