Bumblebees are in our greenhouses for pollination. They are a perfect fit for the job, because a bumblebee will keep pollinating the tomato flower after its first time, whereas bees will keep looking for better flowers and (even worse) will tell other bees, after which they all move.
One of the biggest benefits of bumblebees is that they are always out flying, even when the weather outside is misty, or if it’s raining. A bee, on the other hand, would rather choose to stay in. Bumblebees will always keep going, even if the weather is terrible.