I really don’t like Epic personally, but this is still pretty huge. Linux and SteamOS have come a long way. CEO Tim Sweeney has always been very negative towards the idea of Linux support, so Epic changing that stance would suggest that Linux/SteamOS has finally become too big of a market to ignore.
Competition is good for consumers.
There’s two competitions here, windows vs Linux, and steam vs epic.
Of those two, I consider windows vs Linux the more important competition for consumers. And Linux is the underdog there, so I think Linux doing better will help more people than any other result of this.
So the question becomes, is this good or bad for Linux? More official support for Linux is good obviously, but also Valve funds a lot of open source projects and generally invests a lot of money in Linux (and I’m very doubtful that Epic will do anything similar). So arguably Valve doing better and having a larger monopoly might do more good in the long run, if it helps counteract the windows monopoly. Of course, that would only matter if Epic on Linux actually dents Steam’s market share in any meaningful way, which seems unlikely.