The comparison to a WW2 tank in the Black Forest isn't great though, because the environments live on different timescales.
A forest can regrow and thrive after a few decades. The same is _not_ true for the deep sea[1].
'Life on the ocean floor moves at a glacial pace. Sediment accumulates at a rate of 1 millimeter every millennium. With such a slow rate of growth, areas disturbed by deep-sea mining would be unlikely to recover on a reasonable timescale.'
The biggest player that uses it is Unity, but even they have their own special fork of Mono to get it to play nice.
Full Disclosure: I work for a Microsoft/Xbox Studio.