There are a few advantages:
- A wider knife makes it easier to have more curve at the tip, which is important for a style of chopping in which you rock the blade back and forth quickly
- The weight of the material helps to cut through things when you blade is sufficiently sharp— you lift the blade, then guide it down, rather than trying to forcibly push it down (which is more dangerous if it slips)
- It moves where the center of balance is
- It allows for a knife to have a longer life, as you’re removing a little bit of it very time it’s sharpened
Obviously, you can have a more saber-like design, and still have the curve, but without the weight of the blade, it’s more difficult to chop. And you can add more weight at the bolster to keep it from getting too tip-heavy.
But if you have a store that sells knives near you, ask to try out a ‘carving knife’. It’s shaped similarly to a chef’s knife, but lacks the height. If you’re mostly slicing and not chopping, you may prefer it.
(Note that some people sometimes call slicers carving knives, but those have a perfectly straight blade, and are typically rounded at the tip)