The old heavy polyester double knit quilts from the 70s will be here long after all of us are passed on. They wear like iron. Lol!
I've used poly and poly/cotton blends with no major issues other than needing a cooler iron setting than 100% cotton. They tend to wrinkle less and hold their color better than many all cotton fabrics. Some can be more prone to fraying, but not all. Some doesn't feel very nice, some is great.
I've combined similar weight fabrics of all sorts without problems.
Now if I ever decided to make a show quilt (highly unlikely!) I'm sure I would use exclusively 100% cotton. I use more all cotton than not, but if it is the right weight and color and feels good, that's what is most important for me.