Yes, it is very desirable, but for all devices and different options for them, this probably will not be a nice clean code anyway).
Before iPhone 6 and 6+, we had just resources with scale 1.0 and 0.5. But now, there are some options to use this same res. for new devices, however also if you want, you can provide specific res for each device or reuse 2x for example. I think it's better to give more choices for that.