An unmown, unmanicured lawn, will have a much larger variety of weeds, plants, flowers, etc.
I bet that, after some time, the density of ecologicially-good stuff that sprouts up will be much greater than what you'd get in a manually maintained mulch patch.
I bet that, after some time, the density of ecologicially-good stuff that sprouts up will be much greater than what you'd get in a manually maintained mulch patch.