I understand what you're saying, especially when compared to trillions and trillions (quadrillions?) of tons of CO2 and particulate pollution of coal and oil burning.

OTOH, It would be nice if the nuclear waste could be stored that way. But that concentrated football field can be used for all sorts of nefarious purposes. Ultimately it requires a large amount of infrastructure to prevent leakage, exposure, theft, explosion, degradation of infrastructure, terrorism, etc. So maybe the football field turns into a billion-dollar-a-year "small-town-sized" facility that has to be maintained for as long as humanity exists (10,000 years?). Now it seems much bigger.