Originally posted by chilled monkey
Because without lightsabres they'd get killed.
Misquote on your part.
And we've seen plenty of Jedi in the EU deflect entire swaths of blasterfire with the Force. Tott Doneeta, a random Jedi in the Exar Kun period, blocked fire from the guns of a starship with a wave of his hand.
No, they would get slaughtered. Does the name 'Grievous' mean anything to you?
Grievous isn't a Jedi or Sith, and he's
far more capable than the overwhelming majority of Force-users; more skilled, faster, stronger, and a quicker study.
And so long as you're bringing Grievous up; Obi-Wan, after quickly besting him in a duel, sends him flying several dozen meters through the air with a Force-push when the two are separated by mere inches. Kit Fisto floors him with a similar attack, and Mace hurls him off of a train after a somewhat prolonged duel, again with a Force-push. Some of the only scenes in which he repeatedly dodges Force-attacks are in the last volume of the CWC - which is contradicted by LoE and therefore the G-canon RotS novel - are possibly N-canon, although there may be one in the first volume when he attacks the exhausted, terrified, and stunned Jedi on Hypori.
What's PIS about the fact that lightening would have been useless as they'd have just blocked it?
Palpatine was overwhelming Mace Windu with his lightning while
feigning weakness, and considering he managed to kill two of the Masters in one stroke apiece despite the first strike landing a good three or four seconds after he leapt from his desk, there's no way they would have been able to defend against his Force-attacks; a flick of the wrist or a wave of the hand are all that would be needed to dispose of them.
And most Jedi never even encounter a Sith, so unless they're particularly weak with the Force - in which case they're probably not comparatively good with a lightsaber either (see Johun Othone) - they realistically should be able to do just fine without a weapon.
So again, lightsabers exist to make the movies look cool. It's that simple. Most Jedi and Sith - especially the latter, whom Sidious notes would only use a lightsaber to "humiliate" the Jedi - should have no need for one.