For older "abandonware" games, this is a huge positive. Especially for all the Flash ones. An entire ecosystem used to exist (Kongregate etc.) which was killed off by the ending of the Flash plugin.

For everything else .. well, it's hugely useful to be on one side of it. I was just today getting codex to explain why the Mac and Windows versions of a library I am using behave differently, which it does by decompiling them. We've yet to see how this pans out downstream, but it's quite likely there will be some sort of retaliatory closing of hardware to attempt to fight it.