[TeMPOraL]

I agree. But the thing about trash is, biosphere can't handle much of it. Chucking it into a high-tech hole lets you manage the decomposition, releasing contents over time in form and quantity that the biosphere can safely handle.

Also in general, unsafe things are usually best kept concentrated and supervised. Spreading them all around the environment isn't solving the problem - it's just another way to put the issue out of mind, while future generations suffer from a slow-brew, large-scale disaster.