Do you know that acrylic is plastic? Yes, my fellow crafters, it's ancient dinosaur remains, right there on your bed, on your bodies, in your closets. Not that I mind the use of plastics for things like bullet-proof vests and hard helmets and milk containers but when it comes to yarn, there is a warmer, breathable fiber that I would like to term as wool.
Acrylic does not breathe. Which is why they have warning labels like "Do not put a plastic bag over your head and inhale (but if you do, we thank you for removing your genetic material from our pool)". So you sweat like a dog in it but that sweat is pressed against your body and what does that cause? Yes, absolutely right. B.O. It also has no insulating properties so in the winter, if you're not sweating and stinking, you're freezing. It also makes lousy potholders. Instant burn, yikes!
Wool is made from sheep. Good wool comes from happy
Acrylic does not hold a shape. You cannot block an acrylic sweater and expect it to do anything but perhaps even out the stitches.. You sure can't felt acrylic unless you would like to just take a blowtorch to your hard work and make a drippy mess everywhere.
So what is acrylic good for? No, "nothing" is not the correct answer. I am a big fan of blankets made of acrylic. Baby blankets, large afghans, they're all marvelous. I also like to use acrylic yarn for holding stitches. I have a big ball of blue yarn just for that purpose.
But hey, aren't gas prices high enough? And it's not like acrylic is cheaper. It's easier to find, perhaps, but there are some marvelous places to find wool, both on the internet and with the help of Google, right in your neighborhood.
Please, consider the sheep. Leave the dinosaurs for more noble causes.