So far, the built-in analogic microphones on most librems have a fair amount of unpleasant background noise, like most laptop microphones.
PulseAudio not only has an excellent/true acoustic echo canceller (not just a concealer), it also has a denoiser. Normally, this is used only when the right module is loaded, and only by native VoIP applications. Therefore, it is not used for WebRTC (ex: PureBrowser) and normal sound recording applications.
There is a way to force it for all applications. I have successfully done so by adding some lines to my ~/.config/pulse/default.pa, but this can be done systemwide, like what we see there.
I think enabling it by default (as part of our packages/patchset) would be a great way to improve user experience. Users are always in control as this only creates a second (virtual) device in the sound control center (or pavucontrol) that they can set as the default recording device.