The final message of the video is right on. That is, get a high quality external DAC with headphone output than relying on add-on cards. Unfortunately the way they get there couldn't be more confusing. It is what I call stream of consciousness type of explanation
The other good point is folks running out to buy the Creative add-on card thinking they get better fidelity. They rightly point out that the card may sound worse than what you already have on your motherboard. I have been helping my son with his gaming rig in that same situation. I used to have the card on my older system (it was a Dell and it came with it) and found huge amount of crosstalk with it. I ditched it and gave it to my son. Well, he was hearing all of his PC activity through its output which annoyed them despite myriad of recommendation on gaming forums to buy it. He has gone through a couple of iteration of external devices to get clean sound and he is almost there.
In the video they talk about the O2 "open source" DAC and headphone amp which has good pedigree although unknown performance in the implementations people put out.
They also make good points about needing low output impedance in your headphone driver (driver here means hardware driver or amplifier). But good luck finding that data in any audio solution you buy.