I've run 5 cell packs for many years, since the days of full competition fun fly. I've never hurt an electronic component. I've never seen the need for digital servos, either, so I can't speak for them. Most electronic devices are built with overhead. That is, you won't see 4.8v components on a device rated for 4.8 volts. You'll see standard stuff, usually rated for much higher voltages than we'll ever run. You'll get faster response and more torque at the expense of 20% shorter flight times, but it's well worth it.

FYI: Hitec has listed their servo specifications for both 4.8 and 6.0 volt packs for many years.

Dr.1