From Portals of Phereon Wiki

A dangerous trait that continually stacks Burns on a unit and adds that to their attack power. Note that being Lava Immune does not make a unit immune to Burns.

You'd think this would be the perfect trait for Lava types, but they are completely immune to Burns, not even receiving them in the first place, making this useless for them. Similarly, the Heat Resistant trait will also prevent Burns.

Consider having on units with passive watertrail, as being on a water tile will mitigate Burn damage. Just watch out for terrain changing skills or enemies with the Ignite spell.