The ICE also acts as a battery conditioner, preventing it from discharging below 30% (and thereby dramatically reducing the useable lifespan of the battery, which is a really expensive component.)
A 1.4 Liter 4-Cylinder engine is not something you want to just pull out and pop in with a handle, unless you are a pretty impressive dead-lifter.
When I first joined, I put up a similar thread... and over the months I came to understand just how important it is to use every means at your disposal to help the battery live a long life.
#87 $7000 down $40k ($35k after credit) pricetag. Go Volt!