At some point in our culinary past, we started using a pair of regular old paper-cutting scissors for assorted kitchen tasks, and we never saw any reason to upgrade to kitchen shears! We primarily use them for opening packages and snipping stems off our indoor herb plants, but they've also worked just fine for jobs like trimming pie dough and cutting up a bunch of kale.
The primary advantage of kitchen shears over normal scissors is that they're more heavy duty and can handle a lot more cutting force. Sales people always mention needing kitchen shears to split a whole chicken, and yes, shears are the perfect tool for that particular task. But for how frequently we actually spatchcock a chicken (that is to say, not frequently at all!), we think we'll make do with a chef's knife.
Do you think kitchen shears are a necessary tool? How do you use yours?