It's a nightmare to clean up and never breaks down. Chicken wire in a vase works better for big arrangements anyway. For smaller stuff, try old-fashioned pin frogs or reusable kenzans. You can even use pebbles or marbles. The only tricky bit is tall, single stems, but glass water tubes solve that.
My friend Sarah spent like twenty minutes picking those little foam bits out of her sink drain last week. She said it looked like weird wet confetti, lol. Never going back to that stuff.