I prefer to use all cotton material because it is easier to work with, but sometimes I want to use a blend because I want to use it.
I know it's hard for us after these last 30 years of the quilt police and quilt shops and being told only 100% cotton, but if you go back and look at the magazines and newspaper columns and such, 50-60 years ago there was a lot of praise for the beauty and shine and most importantly, the less ironing of the blends when they first came out as well as the colors.
I'll admit it, I've ironed 100% cotton sheets before but I don't know anyone younger than me that has!
Threads I've only gotten into in the last 10-20 years. I used Dual Duty happily for decades despite the quilt police telling me no. I still have quilts pieced and quilted from 30-40 years ago with it that are holding up just fine, the thread was never the problem (my lack of quilting and hard use/washing caused most of the wear). On the other hand, I have an entire box of mostly rotten cotton thread on wood spools -- which do you think I'm going to recommend using? Right now I'm using Aurifil as my top thread and am piecing with So-Fine as my bottom thread to see how it goes.
And batts? Well, I actually prefer a fluffier softer and lighter poly with less quilting than Warm and Natural with dense quilting almost all the time. Sometimes Warm and Natural is appropriate for my projects, but in general, it's not my favorite. But that's part of my style and the fun thing with quilting is we all get to have our own style.