To implement persistent blockchain-based game-currency long term, the economy is very important.
A lot of games start players off with stuff that comes out of no-where instead of from some already existing part of the game.
If that stuff from no-where actually corresponds to newly minted coins from mining then the same "problem", initial distribution of initial resources, that exists in the games and in the currency can be tightly related, in effect truly just one "problem": the early adopter problem.
If your early adopters are trying to rape the players instead of "farming" them, discouraging them instead of co-operating with them long term to keep growing the economy, the games are likely to become less appealing over time as those early exploiters become more and more effective at driving new players away.
Scratch and burn - keep having to start from scratch as each start ends up with a few "winners" discouraging new players from entering.
A lot of games seem designed to ensure that barbarian hordes are the inevitable winners; even "civilisation building" games too often tend to favour wiping out civilisations instead of co-operating with them.
Maybe though with the right kinds of sandboxes and the right initial core players investing in sandcastles within it, creating milieus / cultures etc that will encourage new players instead of raping them, such players can develop growing virtual holdings that actually appreciate in value instead of becoming less and less desireable over time.
Blockchain based currency can serve as a resource that ties many and varied games together. All the games that allow in game resources to be traded for such a currency become able in principle to trade even if those resources themselves are not directly useful or valuable in the other games.
So far I have been working with two web-based, resource-based games; http://galaxies.mygamesonline.org/
uses energy to mine metal, crystal and deuterium. http://villages.mygamesonline.org/
uses crops to power mining of lumber, clay and "iron" (metal). They thus naturally have metal in common, but blockchain based currency or currencies can also be coded in once development gets to a point where it does not keep breaking new code that tries to add the new currencies.
Blockchain based currency is also so far the main economic link between the web based systems and the Freeciv based worlds of the Galactic Milieu
and the individual character "dungeon crawl" scale implemented by the "CrossCiv" server reachable via the metaserver of the Crossfire RPG