Articulation is much more complex. You go from "vacuum thing I found that looks like trash" to "create a 3D model of this scene, route the robotic appendage thru it, find the ideal grasping point at center of mass, make first attempt, compensate for shift due to wind/previous attempt..." etc.

Then there is the mechanics. Aside from mobility, consider a grasping arm's many servos and wiring harness vs. electric motor goes brr for the vacuum.