Steam has a feature called In-Home streaming where it runs a game on your fast computer and streams it to a smaller/quieter one. It's useful if you have a big desktop box somewhere but your TV is hooked to a weaker home theater PC on the opposite end of the house. Quality and latency aren't perfect, but they're pretty good.
On the Nvidia side, they added a GPU feature to stream things to their Nvidia Shield tablet (Android based, I think).
quarterto is suggesting that if Valve made an iPad client for In-Home Streaming it could compete really effectively against the Shield, since IHS works with both Nvidia and AMD graphics cards and so many people have iPads already.