OOC:
Yea, I mean it's definitely a side quest.
But it would, at the least, provide information that your characters don't necessarily know in character, but that as players ooc you probably know at least in part (depending on how big of a Tolkien nerd you are).
And when you're venturing into ruins, there's always the chance that there "may" be other things found that you didn't know about going into into it too... :)
Basically, for stuff like this, where there may be interest outside of but within the scope of the main quest (or with character background/story stuff), as DM I see it as my job to put story where the interest is.
I'm going to try to make sure it's not a waste of time for us. I'm going to try to make it interesting. I'm going to try to make it challenging (but I'm not going to try to kill you with it).
And also I'm going to try to make sure it doesn't take TOO much IRL time.
Basically - we're not ever EVER going to be just floating in the wind here, doing stuff without reason and risking death for nothing, when I'm DMing. I'm always always going to try to be creating a cohesive and purposeful and mindful and hopefully fun and interesting experience for us as a group.
But if there is more interest in the main quest right now, we can remain focused on that, and always circle back around to this if we want to later.