Yeah that's an excellent point. The Nvidia Shield (Tegra K1) can pull 15-20 watts while gaming. I can play hearthstone for like 3 hours when plugged in.
5V usb port at 2.1A = 10.5W = battery gets drained even when plugged in.
It has a 20Whr battery, if I'm at 90%, and I'm wary of draining it below 10%, that leaves me with 16Whr = an hour at most of gaming on battery alone, on a brand new full capacity battery.
And Hearthstone isn't a demanding title, the streaming works fine but any of the "native" Tegra AAA 3D games kill the drain the device before you finish a level (30min~ and honestly even under that, some games are going to flat out at like 10).
Doesn't help that the device gets pretty darn hot also.
Portable gaming sounds fun until you remember that batteries suck, sure they've improved much but what improved is also the power management.
3D/Graphics are still a power hog, so you get a tiny package with almost no battery to speak off and a heating element all in one.
The Shield is 1900x1200, the Switch will run at 720p in mobile mode, for "performance reasons". Pretty sure they mean for battery life reasons. It will push out 1080p when docked so it's not like the GPU can't handle it.
5V usb port at 2.1A = 10.5W = battery gets drained even when plugged in.
It has a 20Whr battery, if I'm at 90%, and I'm wary of draining it below 10%, that leaves me with 16Whr = an hour at most of gaming on battery alone, on a brand new full capacity battery.