The only value these items have are the value we assign them in regards to the "best relic weapon" or "best relic +1 gear". If SE made them exchangeable on a 1:1 bases the only people losing out are those that sell the currency for gil.

If that's you, I'm apologize... but I am still for it.

Kind of going off topic; can you NPC relic currency? If you can, what is the price difference? I wouldn't know, I never tried. But I'm thinking if you could, their value would be the same.