The Design Insight article mentioned how "Fire smoke terrain" and "Fire terrain" do damage, treating the terms as interchangeable.

However, "smoke terrain" has established rules precedent in this game.

What does this fire stuff DO?

Damage?
Count as Smoke Cloud, with the -1 to attack?
Count as hindering?

Where do we draw the lines?

My interpretation is that it does exactly what Smoke does with an added damage potential.