Round table

Thank you. Now I don't understand why sand is allowed, but mines are not: both are visible to the native unit, which means they are visible to everyone else, so, in theory, you shouldn't be able to cast either one.

Mines don't hinder the attack, but sand is a force that can actually lead to victory.
A long time ago, on the Heroes portal, a monster defeated an incredible army – a hundred units of creatures – with the help of sand. It's a very powerful magic. Mines wouldn't have helped here.