A PSK by nature is a concept of downsizing and compromise. There is a point of diminished returns. I remember a post on another website where empty .22 shells were whistles and the blade on a SAK the signal mirror. It had become a game of minutae and not realistic survival. If you choose to include a blade in your PSK kit do so. Like sleeping bags, In this real world YOU will be the one either warm or shivering in the thing, not a name on a forum half a continent away. That said, the blade will be limited in abilities just as the button compass will get you home, but not to a orienteering checkpoint. Small blades on full handles are nothing new. Oetsi's blade seems to have served him well. The late Chris Janowskie's Ranger knife was such a concept. Perhaps the best resolution to this question is FIELD TRIALS in a controlled environ.