Good combat Knife:
Don't know if you've been in combat, but knife fighting went out a long time ago.
I spend some time as an infantryman in the jungles, Yes, knives were handy. I tried several and settled on a good razor sharp pocket knife which was nothing more then the old army camp or boy scout knife. It was great when carrying a M-60, cutting it out of the vines and wait-a-minute bushes. When it (the brush) got thick, it was opened suppended from my LBE with a piece of 550 cord.
The little pocket knife would cut the vines without a lot of wacking needed by a heavy knife.
It was great for slicing the white bread that came out of C-rats, etc.
In addition to the pocket knife, I carried a M-7 bayonet. Didn't take me long to discard the entrenching tool as too heavy. I could dig almost as fast with the bayonet.
The bayonet was also great for probing for mines and booby traps, (now they call them IEDs).
I think if I was to do it again, I'd replace the camp type knife with a good leatherman tool. It would do the same thing but with an added wire cutter. We use to have to use the three prong flash hider on the 'A1s to cut wire off c-rat cases.
With the weight you save leaving the tacticool combat knife home, you can carry more ammo.
If you do need to poke someone, the bayonet works quite well.