It's been a long week so I'm probably missing this but are you saying there's no such thing as 0.3 seconds? Can't an incomplete pass happen between 1.0 second and 0.1?This explanation doesn't make sense to me. When a clock flips to zero, it's literally zero - never 0.3s - so nobody is getting robbed of any time with the current clocks.
In the NBA, tenths of seconds matter because once the horn blows, play is dead, and it takes a certain amount of time to perform physical actions, like catch and shoot a ball. But in the NFL, a live play keeps running after the clock stops, so as long as it's not zero, it shouldn't matter how much time is left.