Biodegradable pots have their place in the gardener’s arsenal. They are a good choice when starting plants that are sensitive to transplant shock, like melons. But in the context of raising tomatoes, at least on our farm in NW Oregon, I have not found biodegradable pots to be of any particular benefit. In my experience, tomato plants benefit from a bit of root disturbance at the time of transplanting. It seems to slow plant growth for several days while at the same time stimulating root growth. This ultimately results in stronger, healthier plants. You can read more about starting plants from seeds here.