Lightsabres are (big shock) cheap imitations. At the same time too powerful and too limited.
These suckers are good for one thing and one thing only: duelling between people who make Olympic fencers look like kids swinging cardboard tubes.
Part of Dicksons' excellent concept is that the weapons can either attack or defend, BUT the position on the "blade" matters. Their lengths are dynamically adjustable, tapering from base (at where a guard would be) to the tip. The smaller the cross-section, the more powerful they are, so you can block the other's weapon only if you do so farther towards the tip than the point you intersect. Of course if you're quick you can shorten your "blade" to make that happen. If he doesn't do it before you do.
In the end, speed kills. And, yes, that scene above is directly from the story. To the best of my memory Freas never illustrated a story he hadn't read, and although he did "mood" illustrations if there was action in the pic, the scene was in the story.
I am, as always, delighted to be proven wrong. In this case doubly so because that would mean you had once again re-read one of those delightful old tales.