A code update that has something called Steam Cloud Gaming was found by Steam Database. 

It's been reported that Valve might become a competitor in cloud-gaming services. 

If Valve really plans to get into cloud-gaming, it can be seen as a natural evolution of its current system. As for now, Steam players can stream games to devices through Steam Link Anywhere, but you need a PC that can be used as a server.

Steam Cloud Gaming can be beneficial and relevant for Steam since those players, who have got a huge Steam library, will get it all at one - PC play and cloud-streaming. 

But it's probably too early to make any predictions. This is still nothing more than a name in the code, even though the aim of it is quite clear.