Allow people to still spend the money within the market place. The funds would still be placed on a hold so that it can’t withdraw it immediately, but lets players still use their silver from sold items to buy other stuff from the market.
This allows players to spend the money as they sell on the market, but at the same time restricts the ability of gold sellers from selling things on the market and using the silver for gold selling transactions.
This is actually a good idea.
It should also show all the accumulated silver you have through selling your items. Each time you buy an item from the market using the accumulated silver, It gets deducted to the nearest retrievable silver.
All that does is essentially create another “silver pouch” or whatever inside the market. It does nothing to stop the transfer of silver from seller to buyer.
But yes everyone hates the wait times for your silver… Your item is gone and you have nothing to show for it for 48hrs.
I don’t get it 
You have 500 silver on your character.
You sell an item on the market for 1000 silver.
Your silver is on 48 hour hold.
At this point we have 500 on char, 1000 on market waiting.
You buy an item on the market for 1500 silver using the 1000 that’s on hold, and 500 from your character.