The tax authorities consider Silver Coins that have legal tender status as collectibles and art. Therefore, coins such as the Austrian Philharmoniker, the Canadian Maple Leaf and the American Silver Eagle are all taxed with VAT on the profit margin. That is the difference between the purchase price and the selling price. So, effectively, you pay much less tax if you buy these coins instead of the bars.
These silver investment coins of 1 troy ounce of pure silver are traded under the VAT margin scheme
Source: Tax authorities