18v Impact Driver (why not many 3/8)?

[BR3W CITY]

Undoing every bolt on my truck by hand gets old real fast. All the ones I see are the little 1/4" drill-chuck style, or the 1/2-3/4" heavy impact drivers....why no 3/8?

I just want it for stuff you'd normally use a ratchet for, and the light 1/4" units seem powerful enough, but that means using quick-change 1/4 keys, or always running a 1/4-hex adapter for sockets. Why aren't there many 3/8 lighter weight small impact drivers?

When I do need the "Full" impact gun ooomph, I have a nice heavy duty air unit that is plenty capable. I'd just like something that doesn't tax your wrists more than the old ratchet already does!