There is a difference between what is needed for survival and what is functional as a field/camping knife. A larger and heavier knife capable of chopping is practical for camping, and still useful for survival. A smaller survival knife is less capable of larger wood cutting jobs but small enough to actually keep in a kit and still capable of sufficient wood cutting needed for survival.

Basically any durable cutting tool is useful for survival, and better than nothing. The smaller knives with a decent curve for possible skinning and the ability to shape wood or cut small pieces fit in kits better and conform to most laws regarding knives. If it is small, you are more likely to carry it, and it more likely to be available when you really need it.

All of that said, the tools I normally carry, even on commercial airplanes, are EMT shears and a very small saw. For wood cutting a saw is functional and capable. When teaching survival, I generally teach that you can build very good shelters without the need for chopping. The shears can perform most of the cutting jobs necessary, including helping with skinning small animals.

However, as someone who spends a good deal of time in the outdoors, I would rather have a larger chopping tool if I can. Most smaller cutting jobs are done by my SAK, including skinning.