Hi Dwight,
The reason for the existence of Siberian regional coinage, is that the copper ore contained significant traces of gold and silver, but not significant enough to be worth the extraction of these precious metals. As such it was decided to make these regional coins at a lighter weight scale than the standard coinage. For example a standard 5 kopeck of that time should weigh 51.2 grams, so if there was a copper 10 kopecks it should weigh 102.4 grams, while the Siberian 10 kopecks weighs 65.5 grams.
The coins, in my opinion are on par with the coins minted at Ekaterinburgh. Nice examples could sometimes be found. Sigi has many: http://www.sigistenz.com/
I have a couple: