It's curious that none of the folks saying yes to the OP's question about bacteria dosing being useful, and who cited SunnyX and zeovit as evidence, NOT ONCE mentioned the organic carbon dosing part of that bacteria method. (at least not that I saw, perhaps I missed it).
I agree that one of the main benefits of organic carbon dosing is feeding bacteria and other organisms (say, zooplankton that feed on bacteria) that are increased to filter feeders.
Whether one needs to be adding bacteria to accomplish that benefit equally well is the question.
I would add that simple dosing of bacteria without carbon dosing, which seemed to be the initial point of this thread, will also feed filter feeders, but perhaps not nearly as well as organic carbon dosing alone, or organic carbon dosing plus daily bacteria.