Is separating organic rubbish out bad?

I just made a coffee and put the grounds into the box for the compost heap.

Is that bad for the environment?

Having organic rubbish in landfill is surely going to allow microbes to flourish and over a longer time accelerate the decomposition of all the rubbish.

I know some rubbish will takes 1,000s ++++ of years to breakdown, but I would imagine the process would be helped along if the mix of rubbish contained more organics than less...

interesting...