The Windows audio mixer still has issues and Windows still applies hidden APOs that can degrade audio quality.
Some detail can be found in this thread at Audio Science Review:
https://www.audiosciencereview.com/...nding-the-windows-audio-quality-debate.19438/
Elite: Dangerous can be set to use WASAPI to bypass the OS mixer, but this only works if
nothing else is using the device. That's probably where the recommendation you recall is coming from. There are numerous ways you can improve what the Windows mixer is doing, which will allow better audio quality without having to use WASAPI exclusive or ASIO, some of which are described in that ASR thread.
The main things that should be done are disabling extra/hidden APOs, limiting resampling/oversampling by using the correct output bitrate and frequency (99% of the time 24-bit/48kHz is what you want), and preventing the Windows CAudioLimite from adding noise by limiting volume in software (Windows sound control panel) to about 50% (or adding a -6dB offset). You don't necessarily need Equalizer APO, but it does work and is handy for other things.
Also, if you have an older C-Media based Xonar card, I'd recommend the Xonar drivers here, rather than the one's from ASUS:
UNi Xonar drivers main page (information, release notes, driver downloads).
maxedtech.com
Note that those drivers do not apply to any of the more recent Xonar products like the AE, SE, anything with Strix the name, or anything that connects via USB.
Ultimately the differences are going to be quite subtle, especially for someone of your age, but they can definitely be measured.