Obama to this day loves to brag about how he sent SEAL Team 6 to deal with enemies of the US; you can't do that either when you're just a successful author.
Hollande (former French president) also bragged to journalists, many times, about assassinating ISIS leaders.
These are "normal" leaders elected in democracies; it's much worse of course with more authoritarian regimes.
Real power is the power to kill other human beings and not suffer any consequence for it. We don't usually talk about that when discussing politics, but this is what aspiring leaders really crave.