Well the main selling points for me was
1-I could avoid running all the amps of 7 digital servos through the RX. RX power is regulated to 5.0volts, while I get full 6.6volts from my a123 packs to the servos
2- The ease of plugging in 4 aileron and 2 Ele. servos with no need for y harnesses,
and
3-most importantly, the built in battery share

The pin switch is a nice feature, but that's the least important thing in my mind

There are a lot of ways to achieve the same things, Battery shares, Match boxes, Power safe RXs now, etc., there's not one right way, it's what ever you're comfortable with. But the powerexpander has a lot of good features all in one package

I run a optokill switch on all my gassers, just the cheap Rcxel ones, they work great and yes have remote kill function.