Is it possible/worthwhile to fight Zorah Magdaros again?

Solution 1:

Note that the only two ways of farming Zorah Magdaros is either through random events or in multiplayer. There will be a notification once you'll reach high rank that it has been sighted which means you can embark on the quest.

There is an armor for Zorah Magdaros but it's only unlocked once you've reached High Rank (one assigned quest after the 2nd encounter with the monster). So yeah if you want the armor it's worth farming the materials for it.

Since it's a High Rank armor set there are both an alpha and beta version available (with and without sockets). The set has some armor skills that are strong for a variety of different weapons (Handicraft, Hidden element) but it also has some niche skills like improved blast attack or status attack.

Whether or not this is a good set for your playstyle is up to you to decide but it's definitely not terrible and there are certain builds where it is excellent.

If you're interested: Here is a video showcasing the armor and skills on a female character.