Part of the reason shards only sell for 5 electrum is that they are the reward for donating to the game.
Shards are sometimes excluded from rare farms because new players do not benefit as much as they may from other rares, since they only sell for 5, and need 1500 to become useable (apart from a quanta drain)
If Zanz wants donations (which IMO should be separate from cards) then he is likely to want to keep shards less farmed in T50, to keep demand to donate.
If another use for the unupped shards are found, people will ask for shard farms from T50, and there will be many more in the game, which people may or may not keep for later upgrading. (Increased Suppy of Shards, real value falls, less likely to donate)
However, if the rewards become alternate artworks (vrt's Chimera), I think it could be implemented without taking from Zanz's revenue.
Please Note, none of this is actual information from Zanzarino, simply assumptions based on the sell price of shards compared to their rarity and worth, and basic economic knowledge.
Also, it is clear than he is not truly against farms in T50, as they still exist, although they (theoretically) reduce the value of shards already.