To be entirely fair, those three year old PSP emulators still work like a charm. Sure, it won't do N64 emulation, nor DS (which nearly everybody that uses this forum owns some version of), but I don't think either of those are worth buying a $300 device over just because you get some buttons. Really, anybody that has a useless Android phone laying around can use that as an emulation machine easily with the purchase of a $30 controller add on. Even my Droid X can do some amazing things still, and that hasn't been a relevant phone for a couple of years now. Are you saying that it's a smarter investment to drop $300 on a Shield versus $30 on a bluetooth controller/stand attachment? No matter how you slice it, there are a lot of cheaper alternatives to buying a $300 Android device with a built in controller where emulation is concerned.
For streaming, hey, some of us are more comfortable with certain set ups. I'm cool gaming in bed with my laptop propped against my leg (how I browse GBAtemp much of the time), but I get other people would be happy with a slightly more comfortable set up.