Because the world would be a lifeless brown ball of dust without them. Many of these creepy creepers feast on feces (poop) and dead plant an animal matter while adding nutrients to the soil for plant life, which is also pollinated by bees and other buzzing insects. Plants in turn are food for other animals and produce oxygen from carbon dioxide. Insects keep the whole process running smoothly, keeping Earth clean and green.
Insects are the only food that sustains certain species of birds, fish and amphibians. Without insect life, the food chain would be severely compromised, since many higher order animals and birds rely upon lower ones for food. If the insects were to be destroyed, many species would also be wiped out.
When insects appear in your home, remember that the local ecosystem needs them not just to survive, but to thrive. Instead of an all-kill program, make yours an all-clear program. Focus on pest management instead of eradication.
Picture Credit : Google