My Chemical Explosion is not that easy to compare to Miasmatic Putrefaction. The acid is erased from the floor (consumed) as soon as a unit steps on it. The miasma is not consumed in this way. So, if a unit stands in the miasma for the full duration of the spell they will take a lot more damage than a unit who walks onto a single square of acid then stands there. And if one monster is following another towards you, the monster in front will consume all of the acid traps and the one behind will get hit by nothing. Whereas with the miasma, they both get hit with the spell as they walk through it. The miasma is clearly better when you can force a monster to stand in it without moving. This is most commonly done by casting the spell just behind a monster who is in melee range with you then attacking them repeatedly. This can't be done with the acid because for one, you will splash yourself with the acid, and two, the monster only sets off one of the acid traps. The weak acid burn will expire in 5 turns, but the miasma would have stayed there for 12 and done a lot more damage. This is not true. The acid mines are consumed when stepped on. Simply standing in the radius of the initial acid explosion doesn't do any more damage or apply any more DOTs. In order to do that a unit has to walk on additional acid traps, and each trap that gets stepped on gets consumed.