The coins are 1 gram silver, costing 1.5 GPB each. So I did a bit of calculating to come up with the price in dollars per ounce, which are the most common units cited in commodity pricing....
1 gm * 28.35 (conversion to ounces) = 28.35 oz
28.35 * 1.5 GPB = 42.525 GBP per oz
42.525 * 1.639 (conversion to USD) = 69.7 USD/oz
Today's commodity price for silver of this quality is just under $39 US per ounce. Coins do cost a bit more than the commodity price for a precious metal. However, American Eagle 1 oz silver coins were just over $43.00 apiece on Friday. I didn't find any other commodity silver coins available for purchase, but for comparison, the gold commodity price was at $1,649/oz this morning. 1 oz Krugerrands were running from 1,680 to 1,750 apiece, with Canadian Maple Leaf and American Eagle 1 oz gold coins priced similarly.
Purely from the standpoint of an investment in precious metals, the $43 silver American Eagles are worth exactly the same amount as between 28 and 29 1 gram bitcoins costing around $70. Only you can decide if the coolness factor is worth paying the premium, of course. :-) But I recommend keeping in mind that, if the 1 gm silver bitcoin is considered as an investment, it is an investment in something akin to artwork or jewelry. The metal value alone (as with jewelry) isn't worth the price.
This has been discussed a few times in the thread already. I won't get into whether they are a good or bad investment. But the price and premium is comparable to other 1 gram bars and rounds if you search around. You're paying the premium for the size, not for the bitcoin artwork. You get that for free!
P.S. Just an FYI, coins silver is weighed in troy ounces, so there are 31.1 grams in an ASE or Maple Leaf. Worth knowing if you invest in precious metals.