Skeleton Knives are the same quality steel but will have no exterior handle, are light weight and usually less expensive.
The starkness of a skeleton knife quickly reveals that it has no external handle materials. This type of knife can be very handy for a person who needs a knife in a "stay clean" environment - such as a diver or a toxic area safety device.
A great example would be a diver going into a murky area of water. A hand crafted knife with a beautiful custom designed handle will potentially corrode or perhaps retain chemicals under it that will deteriorate the knife over time. Perhaps you are going to be working in a small or tight area. The larger handle will restrict your usage.
On the negative side, skeleton knives can be very uncomfortable - if used for an long period of time. It can also be less accurate to the user because it doesn't have any tangs or guards or a handle to "assist" the user.
Some can be made with a grip as part of the knife handle, but that isn't always the case. The lack of a custom handle will also allow the knife to be weaker in overall design. The handle, tangs, guards, etc. are all things that will add to the design integrity - creating a single larger piece of hardware. As just a basic knife blade - with its own unique handle - it won't have that extra "girth" of a handle, tangs etc. to make it even stronger.
As in all custom handcrafted knives, the purchaser needs to decide what the knife is going to be used for and why. Once that decision is made, perhaps the skeleton knives are the perfect fit for that purchase.
Looking at the larger picture above, it is easy to notice the handle has a definite pattern for a better grip. You will also notice that is is a very thin knife, because of no handle. This type of custom knife allows it to be concealed very easily on a person.