Always a controversial position :-) Back in the day hosting the full development environment would often level out the differences in performance, not as much today. With mobile development you don't have much of a choice, your stuff has to run on the phone.
It still holds though, when developers get to only test on Google Pixie and Samsung S8, while customers are on ZTE Blade, the stuff might even install, but run it won't.
I like to have a decent machine for development, especially when running Visual Studio (which I do not use often, but Visual Studio is not exactly lightweight).
But for testing I absolutely prefer to use a low-end machine. I used to have a SparcStation 20 at home (it died a few years ago, though), and I loved that machine for that precise reason. (Also: Big-endian vs. Little-endian issues) Damn, that beast was SLOW. Not just slow: It only had 64 MB of RAM, and I had removed the hard drive because it was way too loud, so the entire thing ran over the network. Swapping over a half-duplex 10MBit line makes you really think about memory usage. ;-)
