It's still a safety concern to pull that out of the mains (and into your lungs)
You're saying there's a safety concern to pull 300 watts from the wall?
It's safe to pull 300 watts from the wall; your kettle pulls a thousand watts.
The comparison is with pulling it from a battery.
Whatever goes into the lungs either way is a different matter.
With the high powered regulated mod, you can run lower amperage on a bigger ohm coil, but the point is to get 100 watts from a 4 volt battery, that little battery still has to put of 25 amps.
If you were using a 12 volt input via the mains, you'd be running less than 10 amps into the electronics of the device.