The staked maturity is impossible to cash out, you only can exchange your initial staked ICP for staked maturity using liquid maturity. You seem to call « staked maturity » the accumulated liquid maturity, that you could exchange for liquid ICP, as we always could. Anyway, the same quantity of staked material would be maintained, at the minimum.
So there would not be more cash out of staked item, that there is currently. But I see what you mean.
We are just for a possibility to autocompound AND eventually exclusively have staked ICP rather than necessarily having irreductible staked maturity as soon as we would have used the auto compound function.
Plus, the day when You have 0 icp in your neuron, and only staked maturity and liquid maturity, what you see as a way of cashing out staked item would not be possible anymore.
To give a limit case, we should be able to convert a neuron empty of staked ICP and full of staked maturity into a neuron full of staked ICP and empty of staked maturity.