New transplants always get covered for a few days. Wind protection is also a key benefit. My garden is in a very windy spot, and fabrics keep tender transplants from being battered. Hoops allow me to stretch the fabric tightly so the wind doesn't catch it. Earth Staples are essential.
Clothespins are also useful.
I use Hot Caps of various kinds to cover cucumbers, zucchini, and melons. I suppose I could cover them with fabric, too, but since I usually have only a few of each plant, I find hot caps are easier. Add 8 weeks to your growing season with these water-filled Tomato Teepees. They protect to 16 degrees F. Tomatoes are always a challenge in Zone 4. For the past couple years I've used the following system with great success.