When it comes to 3d printed softjaws, I find they can be useable so long as tool pressure is VERY low. At best, you essentially have a light-density softjaw made from plastic. Alternately, at worst, the jaws won't hold anything and are worthless.
We do some production parts with 1/16" endmills using printed jaws, and it works pretty good considering the workpeices are extremely fragile. The tools are barely applying any force. The biggest issue here is accounting for the jaw squish. (see picture below)
Naturally the type of printer and the jaws' orientation during printing will have a large affect on the final properties (accuracy, warpage, direction of layers, jaw resistance to squishing etc). Even when dealing with 100% solid jaws (""""solid"""") you will still have a lot of flexibility as if the jaws were made from a soft plastic like HDPE or UHMW (milkjug). Making jaws from PLA material would be risky due to how prone it is to crack and warp, and trying to save print time by using a partial fill would be asking for trouble unless you actually wanted some compression.
I don't have many pictures of the stuff we do, but here's another one from the opposite end of the coin. It was an ill-conceived attempt to mill out some lathe knobs using jaws with a 5/32" endmill. The workpiece moved around so much that the jaws quickly started to melt. At that point we let it keep going just to see what it would do, lol
Really the programming will determine whether or not the part will survive via light cuts, but the programming is also in control of the elapsed machining time (which decides whether or not it was actually quicker to "do it the right way"). But hey that's always the fun part of prototype work....