It's interesting software. A little complex to setup and use. Lots of filters and modulators.The most extreme ones need a VERY power computer to even run them.
You can use it to give "flavors" to sound. Some people find, for example, that they much prefer the sound of 256 or even 512 DSD and upsample everything to that output. You can play around with the different combinations to see what they sound like.
Personally, I find the differences audible but not overly compelling. I sometimes use it to upsample everything to DSD just for a change of pace. A slightly different sound than PCM.
One of the virtues it claims is that it puts the heavy processing outside the DAC and at the server, so that the DAC "doesn't work as hard" and then gives a cleaner output. I don't know if this is true, but I do find the processing in HQP slightly preferable to that of Roon - but the difference isn't big.
You may or may not find it makes a difference for you. Worth a try via the trial.