This can actually an important part of game, and even story, balance:
Weaker enemies in a game can sometimes be a direct threat, due to lucky hits, or overwhelming the heroes through sheer numbers. The above comic helps demonstrate what might be their true calling: being a distraction. Sometimes, through directly engaging with a hero. Other times, in dividing their attention. Maybe they're a problem because they're threatening bystanders, weaker party members, or even just important "things" (equipment, locations, etc.) but they can go from canon fodder to mattering in an instant. In the above... yeah, just a distraction, but thrown into a time sensitive scenario where giving into the common (and often logical) "Take out all the baddies then proceed." approach could have gotten another party member seriously hurt or even killed.
This can also help "balance" both the action and storytelling when your party's composition is diverse. Uh... modern pop culture/politics makes me feel like I need to stress that I'm talking about diversity in terms of game mechanics, included but not limited to the power levels of the characters. Some GMs and groups work hard to keep everyone around the same level and/or make certain that the different character classes don't have too much overlap in their uses. Dealing with cannon fodder opponents can be a solid way for weaker (whether actually or just relatively) to contribute.
Author Notes: