Robotic mowers are known to improve the quality of the lawn. So the answer is, yes they do. The real question that is to be posted here is how do they help in improving the quality of the lawn? One thing to note here is that saving your time has nothing to do with improving lawn quality. Here is an article by Robotniidukid to understand better.
Constantly Keep Trimming The Grass
Since they are automated machines, they do not need repeated instructions for mowing a lawn. They keep doing it anyway. Therefore, the grass is always kept trimmed and neat. It is essential to note here that the constant trimming of grass is essential for its healthy growth. This practice is known to improve the root strength and sheer resistance of plants.
Keeps Out Unwanted Weeds From The Lawn
In many cases, the lawns are unkempt and there is already a widespread of weeds and weed seeds. In such cases, you cannot completely eradicate them but you can keep avoiding further growth by using robotic lawnmowers.
But normally, these robots can help to keep out weeds. Since they constantly keep trimming the grass, the chances of a weed growing are very less. If you run it once every three days, then the weed seeds would also not spread through the lawn. This is as such because in many cases weeds grow from the niches which will be cleaned through by the mowers.
They Also Help To Add Natural Fertilizers
For any robotic mowers you use, even the one from Robotniidukid, only the tip of the grass is cut by them. There is no possible way to clear every tip cut off so they just remain on the lawn bed. They eventually decompose into the soil and start acting as natural fertilizers. This enriches the grass and also helps to keep weeds away from the plants.