There are statements elsewhere that there's no real point to the HallowNest Seals, and Wanderer's Journals, other than selling them and them being "bankable" Geo.
I'm a completionist and somewhat skilled so I've never lacked for Geo at any point. I recently had 8k Geo despite having bought every item available,
losing 4.5k to the Banker Snail
and
Paying the 3k in the Wishing Well in the Ancient Basin.
I never had any incentive to sell them, so I didn't.
I've now just unlocked
the Grim Troupe, including discovering the Fragile Charms upgrade
and thus suddenly have a need for VAST quantities of Geo.
Before I sell my Relics, does the game give ANY reward for collecting all of those things and not selling them? Any Achievement or acknowledgement from any characters? Is there any reason AT ALL, not to sell them now?
Best Answer
There is no reason to hold on to them until you have them all as you can't sell them in bulk. The game also doesn't give you any completion percentage or achievements based on collecting any or all relics.
On the contrary, relics are designed specifically to be sold. When given to Relic Seeker Lemm, he will tell the player snippets of lore about various pieces of the kingdom's history. If you want to experience all of the lore the game has to offer, you need to collect all of the relics and sell them.
The other advantage of relics over just giving the player a large pile of geo is that relics are not lost upon death. This means that collecting relics is a safe way to hold on to geo until you need it for a specific purpose such as the situation you have described. Now that you have a good place to sink your geo into, you should sell as many relics as you need to buy those items, and take this opportunity to learn more about the world of Hollow Knight.