On an island as big as Duel Academia, it sometimes was hard to remember all the nature around. The school wasn't the only thing on the island.
Other things - like the volcano on one side of the island, the ancient ruins on the other. The large forests that many of the students had gotten lost in.
In a dueling school, it was easy to forget the effects of Mother Nature. They were always there, no matter what.
Which was why, when the students did remember, they thanked Mother Nature as much as they could for what was around them.