there are many players that have massive amount of umbral shards in their inventory with no use due to max gear and expertise.
So, why not giving those Umbral Shards a meaning by allowing to upgrade gear with Shards without having to bind it and therefore allow the selling of 625 gear.
There would still be the expertise system that would reduce that bought 625 item to the specific expertise level.
This would also discourage the selling of Umbral Shards (M10 Final Boss), since they would gain a value then.
Price is define how much someone want to pay for it and what you need. I paid for my BiS parts shirking fort, resilent refreshing evasion 40k each in Dry Tree.
If u search market you can buy everything you need for pennies just be patient and do not rush for BIS… its really sad when u buy 1 BIS item for 150k and next day u get exactly same from OPR chests … for free