What kind of cooking knife is this

Advantages

• no hand needed to hold the food, therefore safer for children or those lacking knife skills
• quicker for those lacking knife skills
• no need for gloves when cutting foods that can irritate the skin, like chillies.

Disadvantages

• Awkward and dangerous to wash in between the blades for the double-blade version.
• Difficult to store safely
• A unitasker really only suited for chopping herbs and spices. The most common items chopped in many cuisines, onion and garlic, would require rough chopping first with a traditional knife, making it hardly worth it.
• Inhibits the development of valuable knife skills.

There's no question that a 4 or 5 inch utility knife is going to see a lot less use than your chef's knife or your paring knife, both of which have innumerable uses. The utility knife is a lot more specific, really being for cases where the paring knife is too short and the chef's knife is too heavy or thick. I have a 4" utility knife, which (of course) I got for free with a 6" Sabatier chef's knife. It gets used a couple times a week, for:

• scoring onions in order to mince them
• cutting limes in half (a chef's knife seems like overkill here)
• splitting small peppers
• slicing large California shallots
• cutting cheese

... and similar occasional, accessory uses.

Part of the problem with the 4" utility knife is that it's really a dwarf 6"-8" utility knife. The 6" or 8" utility knife, now commonly called a "vegetable knife", is far more useful; the long, thin blade is excellent for making paper-thin vegetable and fruit slices, and can be used as a fileting knife if you don't have one. At the 4" size, though, the utility knife is useful only for cutting things which happen to be small, and only if you don't already have a more general knife dirty.

If what you're really asking is "can I get rid of this knife?", the answer is "yes".