I am not sure about keeping fish this way. The plastic of the container will be in the water. I assume you live in a country with a good temp and a thermometer and filter aren't needed.
If it comes to that I envy the easy way you can keep them.
I hope they live a long life and the water will not heaten up by the sun.

For sure it is a handy way of lifting it and way lighter than a glass tank.