If you autodetect hw accel, even the slowest underpowered gpu might get returned, which could result in worstened user experience compared to just using cpu.
the trick is lots of amplification on both ends is able to compensate for a wide beam spread, edfa's allow you to optically amplify the sent signal and allows the faint received signal to also be amplified
Spectrum or not, this is not a problem of weakly specified input, it’s a broken logic.