Why attenuator and not filters for QC driving line

In all the cold quantum computer designs (superconducting qubits, spin qubits) attenuators are put on the driving lines. Their role is to kill the noise spectral density that comes from higher temperature stages, such as the Johnson Nyquist noise. Indeed the pulses are generated at high temperature and may contain a lot of noise that is required to be killed.

My question is simple: Why do people put attenuators which dissipate a lot of heat, and not simply filters? Indeed the goal is to kill the noise at qubit frequencies. Filter that do not let pass this frequency would be enough and can not be dissipative.

The filters help in reducing the out-of-band radiations in the system, but quantum measurements are not only susceptible to thermal radiation or external noises. For fast computation using transmon qubits, a DRAG or Derivative Removal by Adiabatic Gate in which a fine-tuned of out of phase pulse is applied, proportional to the derivative of the original pulse which will increase the fidelity to about 99% and hence, we minimize leakage of information. So, we do not want to filter out this pulse.

Similarly, for a larger number of qubits, we'd have to tune in and out of resonance to control the transition frequency which is done by applying current to the flux bias line. In QED you have resonators for carrying out coupling and readout and the flux is generated in the circuit which detunes the qubit from its operating frequency and adding a significant phase to it and this is taken care by applying pulse shaping techniques like fast adiabatic pulse and controlling the energy state of the qubit. So, you can definitely not use only filters at every stage of the quantum process and hence attenuators are used instead but at further steps, you can add filters like when you are dealing with distortions of electrical components where you can desert the extra frequencies.

Though this still is quite a challenge as we can still not correct distortion with precision maybe if the approach is changed we can do that, but the effective one right now as I discussed in case of superconducting qubits will require attenuators in the cables for experimenting with charge qubits that are as you specified driver lines that as I have read are used for controlling the quantum states of qubits with a microwave tone realizing single-qubit gates, and for probing the frequency shift of readout resonators, the flux lines, and the output lines.