"Can be as expensive"?!?! You jest, surely? You have to *really* look to find a high-end factory-made electric guitar much over £800, whereas you've hardly even got into the price range for a good factory-made acoustic.
Re Misophist's argument about amplification covering up mistakes, I think he's dead wrong - it's the other way around, particularly as far as left-hand technique goes. String noise, fret squeak, buzzes, brushing an unfretted string, etc are basically imperceptible on an acoustic bcos the strings being played are much louder. If you put it through some gain on an electric though, and every little noise like that comes through the speakers like God's footsteps! Acoustic players can get away with stuff which electric players can't.
I've got no argument if you say that a high-gain electric has no place in playing a slow Irish air. However I'd also stipulate that neither do the bodhran, banjo, melodeon or hurdy-gurdy, and bagpipes certainly aren't a good idea in an enclosed room either! Choose your music and choose your instruments to suit. And for the record, there's some damn good folk-rock outfits out there who *can* make electrics work in traditional tunes, basically bcos they're skillful. It's not the same as a traditional tune played acoustically, but it's no better or worse for that.