Quoted for emphasis. We can use what ever top quality DAC's we want. If someone uses a PC music server, there is no insertion loss. We can of course how that DSP tool is used, and uses range greatly. In exceptionally symmetrical and acoustically balanced rooms with well behaved speakers, less is more. Even in those rooms there can be room to fine tune and I'd argue that in the right hands such adjustments are far superior and precise than some of the fine tuning resistor adjustments I see on some speakers like the big Wilson's. The biggest difference is there's much more rope to get tangled up in vs 2-4 limited options to choose from.
DSP doesn't have to be full impulse response correction and attempts to fix acoustic problems. Today we have dramatically better tools than in the early days of a bench top RTA with LED strips which are available for less than the audio connectors and power receptacles many are using. They require knowledge, experience, and skill to get the most from them, but that's true of most any specialty tool.
Yes, there are some who get caught up in the advertised "automagic" capabilities of DSP. Anyone who well understands optimizing an audio system should know the best results come from getting the most from the physical setup and minimizing unwanted acoustic problems, especially at higher frequencies. What DSP or any signal EQ/processing can afford you is an added range to consider during the physical setup. A great example is when you face setup issues resulting in significant depressions/dips in the bass energy at the listener (say below 200Hz). In some cases there will be other placements which will fill in the worst valleys, but leave a peak or bump which might be objectionable in listening. With DSP available in the digital chain you can directly smooth that peak and gain back the detail and improve the balance that would have been present with the valley in the response. With the constant push for purity of signal, leaving most of the final voicing choices to the speaker and room interaction, most audiophiles greatly underestimate the audible significance of subtle shifts in broad spectral balance. Given the wide ranging sizes of our listening rooms and energy decay vs frequency, such adjustments can be invaluable if not overused. Many of the big 2-piece reference speakers with separate woofers are able to use the separate woofer and crossover adjustment to execute this bit of matching to the space, but because it's at the speaker level the end result adjustments get overlooked from a system perspective.
As I mentioned before and more than a few have echoed, the top point of focus with any digital adjustments should be if and how analog signals have to be made digital. The quality of the output DAC should be given the same consideration as in any state-of-the-art system. Signal levels are critical for optimal ADC, so putting this after a volume control needs to be considered carefully. The wider Voltage range we have to account for, the less optimized the conversion, and the more detail which can be lost to accounting for maximum levels. Source conversion to digital has the benefit that we have known signal ranges coming out of say a phono stage or R2R player. The only case where I find the post volume control ADC a worthwhile compromise is in the subwoofer range, but if given the option I would always prefer this done upstream.