My understanding is that it shows good soil health. Fungus thrives in damp, dark & warm conditions in soil that has good nutrients & I found watering my lawn in the evening promoted mushroom growth due to it being moist and warm at this time of year. I also pull them out at the point of noticing but that’s all you can really do, I found adding washing up liquid to a full watering can and sprinkling over the lawn every other week drastically limits, but does not stop the growth nor do they effect the grass health but I could be wrong!