I did Krav, Jiu-Jitsu and Muy Thai for a while. The biggest take away for me was the confidence boost, knowing with 100% certainty what I and my body can do.
I looked great too, but that was secondary
Buuuuut on the downside, I broke my collarbone and tore a muscle in my shoulder and it’s never been quite right since. Take Krav seriously
Bluffing as in saying you’ve had training? That’s a bad idea.
A huge portion of martial arts is learning how not to use martial arts. De-escalating, removing yourself from the situation, choosing your battles. If you feel the need to bluff you’re almost always better off just walking away.
One of the big lessons in Krav is that every confrontation is deadly. Not could be. Not might be. Is. In the real world it can only take one lucky punch to kill someone, even if the person throwing that punch is completely untrained. Every opponent on the street is armed, dangerous, and actively trying to kill you if you’re being attacked- that’s the mentality
You avoid fighting in every capacity possible, it’s an absolute worst case scenario. But if you have to fight? You be incredibly violent, dirty, and lethal. You aim to maim your opponent and get to safety- because assholes that start fights tend to run in packs. From that perspective them thinking that you’re untrained in an advantage because they won’t expect it.
Tl;Dr, I would rather bluff that I can’t fight than let them know I can
To answer your second question, yes it’s worth it for everyone to learn some degree of self defense skills, if only for the physical benefits