"It's literally tens of millions of hours." Xbox CEO Phil Spencer celebrates Xbox Cloud Gaming's "dramatic growth," now with per-device usage charts.

How's Xbox Cloud Gaming doing? Pretty well, it seems.

A few years back now, Microsoft introduced Xbox Cloud Gaming to the world, after years of research and rumors. As Microsoft Azure's cloud infrastructure expanded and matured, so too did Microsoft's opportunity with Xbox Cloud Gaming.

Now, we've seen the service expand, improve massively in quality and speed, gain a huge array of Xbox Cloud Gaming accessories, and now, you can even stream an expanding variety of games you actually own. Are people actually using it though? The answer seems to be a very definitive "yes."

In a recent interview with iJustine, Xbox lead Phil Spencer described where the platform is heading, and how well Xbox Cloud Gaming has been performing in recent months.

"We always tend to just follow where we see people playing. It's just been amazing to see the number of people now that are playing Xbox via cloud. It's literally tens of millions of hours every single month, and growing dramatically."

Yesterday, Microsoft shared (via @Welfare_JBP) a recent GDC session on Xbox Cloud Gaming, and included a full breakdown of how users are engaging with the platform. Surprisingly, Xbox One takes the lion's share of use, as more and more games skip native Xbox One versions in favor of Xbox Series X|S and Xbox One cloud streaming. Very close behind is smart TVs. The modern Samsung range has Xbox Cloud Gaming built in, which is quite handy.

Surprisingly on the low ebb is smartphones, which is where I think many would've expected more use. I think the reality is that smart phones and touch controls aren't a great experience, owing to screen size. Most games are simply designed for TVs, with zoomed out cameras and smaller fonts.

In the GDC talk, Microsoft explained a variety of new ways Xbox developers can leverage cloud gaming, including cloud-aware user interfacing for scaling on smaller screens, unlocking the 16:9 aspect ratio to adapt more screen sizes, and much more.

Indeed, most of the issues around Xbox Cloud Gaming, Xbox Play Anywhere, and more, simply represent development hours and polish. Spencer acknowledged some of the issues fans are running into "discovering" the Xbox ecosystem on PC, noting "we have a lot of work to do there."

Only yesterday I wrote an article complaining about how the Xbox app on PC handles library curation, which is inexplicably showing Windows Phone games recently. A source confirmed to me that, that, was in fact a bug — part of on-going work to unify Xbox's store listings between console and PC.

"Obviously with people finding Xbox on PC, we have a lot of work to do there. We've teased and talked about handhelds, and I'm very excited because we both travel some, and sometimes you can't always take your console or whole gaming desktop with me."

But it is really about building the experience around the person — and that's the part that gets me most excited, not a single device at the center. It's not one game. It is the player at the center, making sure all of your games are available, all of your save games all of your entitlements are available wherever you go."

As someone who is actively using Xbox Play Anywhere, I share Spencer's excitement for the future of the platform — but execution is absolutely key.