It's notable for two things...
1) The iconic Superman image breaking the chains around his chest by flexing (it originated here as green to represent kryptonite but was later used with the chains coloured grey for ordinary metal) .. and that's much more iconic than Superman munching a rock.
2) This arc represents how early on DC realized that Superman had gotten stale and overloaded with useless, sometimes silly additions to the mythos... like the fact that Kryptonite got to be more common than gravel. A 5 year old kid could go out in a field and just pick up a hunk of it. While Truer clings tightly to the lightheartedness of the earlier days of DC, the company itself was losing ground and money on their number one character and needed to take action. This arc was a first attempt at what later resulted in a complete reboot of the character by Bryne and Wolfman. (Contrary to what some may tell you here, the reboot was not Byrne's idea. He wanted to introduce changes within regular continuity. It was the decision of management to take a clean, fresh start with Superman.)
So - is it worth picking up. It's notable for the reasons I said. Historically speaking, it's something I appreciate having in my collection. From the standpoint of continuity, it's not needed.
Denny, however, is a good writer and it's not a bad read.