The DOT on Maliwan guns can actually be higher than the gun itself with some legedaries. Some of my guns do 10-12k damage a tick. But year don’t become reliant on it.
To OP: Infusion overall isn’t a good skill. It is almost always a damage decrease. If your action skill is the same as the gun then there is no difference in the initial bullet damage. If your action skill is not the element of your gun then you going to do less damage.
If your gun does 1000 corrosive damage, your element is fire, and you have 5 points in infusion. So now you are doing 600 corrosive damage and 400 fire damage. If you are lowing the damage, and this is without any element bonuses. Fire on armor will be even less damage. It’s good for leveling or for a Jacobs build, but I don’t know if even @Derch is in love with it or not. And he made a Jacobs only build.