Just setting aside the dearth of models with jammers that are specialists - because isolating a TAG in ARO with a low damage attack is not nearly so good as possessing a TAG in ARO with a very high damage attack. And just generally the overall AROs available to AHDs, while less universally applicable, are more powerful (with either positive WIP mods or higher damage or just better effects, in the case of possession). Also, an AHD turns every repeater into a projected threat. Jammers are useful tools. They're also overrated.