When i say share i mean they copy the ones already downloaded
Blindingly fast on the response you are!
But they're changing their patching policy. They're no longer going to keep a patch in beta status for months on end, the games would be updated frequently, and they've even stated here that they're not so sure they'll even do beta patches for Crusader Kings 2.
In the normal nature of things, I'd expect Paradox's level of support effort will be highest for a few months early post-release and decline over time to a much lower (but significant, if Paradox performs to past standard) level as the months and years roll by (I'd expect for the copies of the game I expect to buy to see use for years). It is probable that the intervals between updates will lengthen, particularly between the standard patches.
There is also the concern someone previously expressed that even standard patch updates on a secondary version may lag those on the favored version (e.g., due to personnel time constraints), easily leading to periods of mismatch among players playing different versions.
Such a discrepancy, if it arose, is a multiplayer problem, and an impediment for mod development and use for anyone using a laggard version. Differences of a day or two are annoying and can be disrupting, those of a week, or month, or more could be aggravating. This will be an issue for a minority of players who get involved with mods or multiplayer or would receive some practical benefit from the latest version.
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P.S. Remaining unanswered by anyone that I can identify as offiical is my question whether a GG installation on one machine can be beta updated by copying files from a Steam beta installation on the other. This is a technical question. However, if the Steam license will allow me to use beta versions while the GG license will not, technical feasibility is irrelevant since use of beta on GG would be impermissible.