妙法蓮華經玄義 4.173

4.173

復次，三乘同得神通，而二乘不能用成就眾生，淨佛國土，故不受遊戲之名；菩薩能爾，故別受遊戲神通名也。

Furthermore, the three vehicles all attain spiritual penetrations, yet the two vehicles are unable to use them to mature sentient beings and purify buddha lands, so they do not receive the name "roaming freely"; the bodhisattva can do so, and therefore specifically receives the name "roaming freely with spiritual penetrations."