I love the way you say it so casually. In the grand scheme of things you are of course right, but I reckon converting a coal plant to gas is a non-trivial undertaking.
I'll assume any hydro opportunities are tapped out. Conservation is already big in Germany.
Wind and solar can only go so far. And natural gas would provide better peaking capacity to balance it out.
I mean, yeah, it's slightly ironic, but is it not irrelevant?
The only reason to do so is to end up with high value in "biofuels" category. Just for show.