Although DCM can be used, it has several disadvantages.
As a chlorinated solvent, DCM tends to form emulsions, especially in basic environment.
DCM is also slightly polar, so it pulls little bit of water, part of it dissolves into your aqueous layer and it tends to pull lot of impurities. So ideally it should be dried after combining the DCM pulls (e.g. with calcium chloride). This is not an issue with truly non-polar solvents as they pull virtually no water.
Salting out would be less efficient with DCM as it can dissolve DMT salts too, to an extent (don't know about fumarate though). This is due to its polarity and partial water miscibility.
Aliphatic (heptane, naphtha) and aromatic hydrocarbos (toluene, xylene) work well for backsalting.
DCM is easy to recycle by distillation due to its low boiling point, but it grabs lot of organic impurities over time that cannot be easily removed by distillation. I have recently purified my DCM (it has to be shaken several times with sulfuric acid, then with water, then base, then water, then dried and then redistilled) and even though it looked clear, it was actually very dirty as the acid turned dark red on contact.