Yeah...
First. LYT dominated and shocked wulin. Enough to build the reputation of his escort company. Enough that wulin was still lusting for his power two generations later. I'd say that's pretty good.
Second. We have every evidence that any sharp weaponry can injure even someone with extreme internal energy. Supreme internal energy has been shown to reduce fatal damage to merely severe damage, but it required specific techniques to actually stop a blade.
Third. PXJF's power was never brought into this. The point was that you could get close, stab the person and get out without being countered because of the extreme speed. However, its power is rather significant since we know that DFBB's internal energy was significantly higher than LHC's (from the shock LHC felt) and probably even RWX's (because RWX pushed so hard that he was breathing harder while DFBB's breathing was still casual).